Water & Sewer Authorization Manual

Chapter 1:  Introduction

A.  Organizational Outline.

The Washington Suburban Sanitary Commission (WSSC) is a bi-county agency which was established in 1918 by an act of the Maryland General Assembly. It is chartered to plan, design, construct, and operate water and sanitary sewer services for nearly all of Montgomery and Prince George's Counties, encompassing a 1,000 square mile area. Excluded are Rockville and Poolesville in Montgomery County, Marlboro Meadows and parts of Bowie in Prince George's County. Since inception, the WSSC's service population has grown from 30,000 people in 1918 to 1.4 million people. It now ranks as the 7th largest water and wastewater utility in the nation.

Each year the WSSC systematically meets the water and wastewater needs of a growing population. On average, approximately 275 new projects are authorized yearly; at any given time roughly 100 projects are in various stages of design or construction. The WSSC competitively bids those projects that it constructs. Applicants have the option of designing and constructing the facilities necessary to service their property. In either case, WSSC reviews the design and inspects the construction for each project. Large and small projects alike account yearly for 60 miles of new water main and 50 miles of new sewer main to accommodate 6,200 new customer hook-ups. 

B.  Construction Funding.

The Commission funds its projects under two basic construction funding programs - Water Supply Bonds and Sewage Disposal Bonds, and General Construction Bonds. There are several other minor sources of funding. 

1.  Water Supply Bonds and Sewage Disposal Bonds

These are used to finance major facilities such as treatment plants, pumping stations, storage facilities, water supply mains 16 inches in diameter and larger, and sewer mains 15 inches and larger. Generally, these projects are included in the Commission's Capital Improvements Program (CIP). These bonds are repaid primarily from customer water and sewer bills. 

2.  General Construction Bonds 

These are used to finance the construction of water mains 15 inches and smaller and sewer mains 14 inches and smaller. These bonds are repaid by Front Foot Benefit Charges levied on properties abutted by the mains.

3.  Other 

There are several other sources of funding which the Commission uses to fund its projects.

a.  Federal and State Grants: Federal and State Grants to fund portions of major wastewater facilities.

b.  Sub-District Fees: Special fees charged to new development in designated areas to offset the increased cost associated with unusual conditions of providing service to the area. These are currently six areas that have Sub-District fees. These are as follows: 

  • Piney Branch
  • Mill Branch
  • Green Branch
  • Olney (James Creek)
  • Clopper Road 
  • Mattawoman / Timothy Branch

Appendix A includes a list of sub-district fees and maps identifying the areas affected.

c.  System Development Charge: This is a charge to new customers to pay for the major facilities in the Commission's Capital Improvements Program which are needed to accommodate growth. In the event a property lies in a sub-district, the Sub-District Charge, or the System Development Charge, whichever is greater is required.

d.  Deficit Payment: A payment required of an applicant for water and/or sewer service which will make it economically feasible for the Commission to provide the requested service. The method of calculating deficit payments is described in detail in Chapter 3.

C.  Water Distribution System Synopsis

All finished (treated) water leaving the Potomac Water Treatment Plant (WTP) must be pumped. Depending on destination, water leaving the Patuxent plant is either pumped or it flows by gravity. In Prince George's County all is by gravity flow; in Montgomery County all is pumped. From a system standpoint, 55 water-storage facilities and a network of 4,800 miles of main handle a volume in excess of 170 million gallons per day.

Because of variable ground elevations, the WSSC's water system is divided into pressure zones which are hydraulically separated. The WSSC water system ranges from a low elevation of 10 feet above sea level in Prince George's County to a high of 845 feet in Montgomery County. To provide adequate pressure to such a range in elevation, each pressure zone is isolated from adjacent zones by division valves. Each pressure zone has a source(s) of supply (treatment plants, pumping stations or valves) and a transmission system to convey water from the source to the points of use. Water pressures are raised by pumping stations or reduced by pressure reducing valves between pressure zones.

D.  Wastewater System Synopsis

The WSSC's wastewater facilities can be divided into two functional types: wastewater treatment and wastewater collection. WSSC operates five wastewater treatment plants and has a combined capability to treat an average daily flow of over 75 million gallons. WSSC is also entitled to treat up to 153.3 MGD at the Blue Plains Regional Plant (expanding to 169.6 MGD) and 3 MGD at the Mattawoman Plant as a result of regional agreements and payment of appropriate capital and operating expenses.

The WSSC wastewater system consists of both gravity and pressure sewer systems. There is over 4,700 miles of sewer pipe and over 40 wastewater pumping stations. Gravity sewers within the network range in size from 6 to 102 inches in diameter. Small diameter, low pressure sewers range from 1 1/4 to 4 inches, and require each property to be served by a Grinder Pump Unit. Each drainage basin is associated with a major stream or river, with each stream having one or more trunk sewers traveling along its course. Wastewater pumping stations convey wastewater through force mains between basins. Wastewater pumping stations may consist of several pumps capable of pumping over 300 MGD through a 108-inch force main (e.g. Anacostia) or limited to a single pump with a small pumping capacity (e.g. Muirkirk).

E.  Types of Water and Sewer Service

Depending on the location of property, an applicant may require one or several forms of WSSC service. This depends on the location of the property in relation to existing water or sewer facilities. The following definitions pertain to the different types of WSSC service and each type of service is also shown in the following sketch.

1.  Extension 

An extension of WSSC's water or sewer mains from the existing end of the system to the property requesting service.

2.  Connection 

A connection, also called a house connection, is the service line from the WSSC main to the property line.

3.  Hook-up  

A hook-up is the joining of the on-site water or sewer line to the connection at the property line.

F.  Fees and Charges

Depending on the type of service required and the scope of the development, an applicant for service will be responsible for various fees and charges. These range from a Report Review Fee which is required with any Extension Application, to the monthly or quarterly water/sewer bill to pay for water and/or sewer usage. While they are described in various sections in this manual, Appendix J contains several documents showing the possible fees and charges.

G.  WSSC Service-Time Staging

The location of existing water or sewer mains in relation to the property requesting service will dictate WSSC's processing action. The flow chart shown in Appendix B outlines the major steps for connection or extension service requests. A connection to an existing line takes about three months--assuming other agency criteria has been satisfied. Design and construction of a mainline extension ranges from 6 to 8 months for a short extension (if not slowed by special permits and rights-of-way) to four or more years if Capital Improvement Program projects are involved. If a CIP project is required for service, the applicant must consider this time constraint in their scheduling activities. The typical start-to-finish time for providing service to a subdivision is between 16 to 20 months. This time is from the county's approval of the preliminary plan to the completion of construction of the water and sewer mains. This time frame assumes no major delays due to off-site right-of-ways and outside agency permits and that the developer and his engineer properly plan their other site work.

H.  WSSC Service Requirements

Prior to requesting service from the WSSC, other regulatory requirements must be met. These include:

1.  Service Area

The WSSC is prohibited, by law, from constructing mains to an area not planned for public water and sewer service. Service area categorization (designated by special maps) is the responsibility of the Department of Environmental Protection in Montgomery County, and the Department of Environmental Resources in Prince George's County. Unless a property is situated in the appropriate service area, the WSSC cannot accept a request for water and/or sewer service. The property must be in Service Area 1 through 3. Preceded by a "W" for water and "S" for sewer, the numbers below correspond to County and State established service area categories: 

Montgomery County        
1 = Mains exist or are under construction.
2 = Mains are in final planning stages.
3 = Service is planned within 2 years.
4 = Service is planned within 3 to 6 years.
5 = Service is planned within 7 to 10 years.
6 = No planned service  

Prince George's County
3 = Service may be provided.
4C = Conditional approval for category 3
4  = Service is planned for the near term.
5 = Service is planned in the future.
6 = No planned service

2.  Allocation Policies

Montgomery County's sewer allocation policy enables any applicant to apply directly to WSSC for service in those areas already established as Service Areas 1, 2, and 3. The same is true in Prince George's County for Service Area 3, except for projects undertaken by a public entity. These projects must obtain a Public Use Allocation from the Prince George's County Department of Environmental Resources prior to applying for service from the WSSC.

3.  Preliminary Plan   

If a Preliminary Plan has been accepted for processing by the Development Review Committee of the Maryland-National Capital Park & Planning Commission, WSSC will concurrently accept service extension applications. The preliminary plan, however, must be approved prior to the WSSC's approval of the authorization.

4.  Utility Line Concerns and Constraints   

Site planning concerns worthy of note are:

  • Other utilities cannot accomplish their site-supportive work until WSSC construction is finished. Early coordination with other utilities is encouraged. 
  • A developer of a site is responsible for gratis dedication of any easements or rights-of-ways necessary on their property for the installation of public water/sewer mains. This includes those rights-of-ways necessary to provide future WSSC service to others. 

I.  Staged Construction 

Larger projects, especially those requiring off-site rights-of-way or CIP facility construction, lend themselves to staging of construction in parts. For example, a water or sewer extension involving extensive off-site construction might best be staged so that site work can be done while awaiting the off-site construction. Also, staged construction staggers financial outlays--such as deficit payments (explained in Chapter 3). Finally, staging should correlate the availability of water and sewer mains to realistic marketing projections. Limited capacity of existing water and sewer systems may also necessitate staging the development.

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Chapter 2:  Water and Sewer Service Development

A.  Applications For Service Extension

If it is necessary to extend the Commission's existing water and/or sewer system to provide service, an Extension Application must be submitted to the Water and Sewer Reports Section. This application is processed as an Engineering Feasibility Report, which details engineering and economic conditions which must be met before service would be provided. Following approval, the report becomes an Authorization. For private citizens and non-profit organizations, the WSSC (Water and Sewer Reports) staff will prepare the report. However, all other applicants must engage an engineer to prepare the report. A sample report is shown in Appendix C. 

B.  Engineering Report Processing

As detailed in Chapter 1, there are a number of regulatory requirements which must be met before service can be requested from the WSSC. Once accepted for processing, the engineering report is internally coordinated and reviewed by WSSC offices before being submitted for approval. The scope of the project determines the approving authority in accordance with the Commission's Delegation Of Authority (See Appendix D). To expedite the service process, the WSSC Water and Sewer Design Section will accept private design plans for review purposes in advance of authorization approval, but withholds sign-off on plans until a project is authorized. An applicant who proceeds in this fashion does so at their own risk and expense. 

C.  Authorization Implications and Limitations 

All finished (treated) water leaving the Potomac Water Treatment Plant (WTP) must be pumped. Depending on destination, water leaving the Patuxent plant is either pumped or it flows by gravity. In Prince George's County all is by gravity flow; in Montgomery County all is pumped. From a system standpoint, 55 water-storage facilities and a network of 4,800 miles of main handle a volume in excess of 170 million gallons per day.

Because of variable ground elevations, the WSSC's water system is divided into pressure zones which are hydraulically separated. The WSSC water system ranges from a low elevation of 10 feet above sea level in Prince George's County to a high of 845 feet in Montgomery County. To provide adequate pressure to such a range in elevation, each pressure zone is isolated from adjacent zones by division valves. Each pressure zone has a source(s) of supply (treatment plants, pumping stations or valves) and a transmission system to convey water from the source to the points of use. Water pressures are raised by pumping stations or reduced by pressure reducing valves between pressure zones.

D.  Transfer of Authorization

A water/sewer authorization is granted to a specific applicant for a specific property. If there is a change of ownership of the property that is the subject of an authorization, the authorization must be transferred to the new owner. This is accomplished by submitting an Authorization Amendment form to the Water and Sewer Reports Section along with the Transfer of Authorization fee. The form must have the signatures of the present and proposed authorization holders, or a copy of property ownership must be provided. Once approved, the new authorization holder will be obligated to fulfill those conditions previously set forth by the Commission. It is important to keep authorization ownership current, since any refund of a deficit payment due to recosting is payable to the applicant of record at the time of recosting.

If a portion of an authorization is transferred before WSSC construction is completed, the transferred portion will be converted into a new authorization. Each authorization will then be costed and conditions adjusted accordingly, based on circumstances current at the time of transfer.

E.  Conceptual Water and Sewer Guidelines  

1.  Water Systems Fundamentals

  • The following factors apply to mains 12-inches in diameter and less. 
  • ‚ÄčThe water main is to be located within street rights-of-way whenever possible.
  • The water main should be located within the pavement of proposed streets.
  • The water main should be located outside the pavement and within the street right-of-way of existing streets.
  • The water main alignment should avoid the removal of trees and landscaped areas within existing streets.
  • The alignment should allow construction without the need for closure of existing streets.
  • The alignment should avoid high traffic volume roads, if possible.
  • The alignment should provide for future extensions without the need to cut the pavement of proposed road improvements.
  • When the water main must be outside of a street right-of-way, steep slopes, wetlands, tree save areas, parklands, and other sensitive areas should be avoided.
  • When outside of a street right-of-way, the alignment should follow property lines.

2.  Water Systems Fundamentals

The following factors apply to gravity sewers. Grinder pump systems are addressed later in this section. If service will require a pumping station and force main, the applicant's engineer should consult with the WSSC.

  • Normal sewer is 8 to 10 feet deep. Sewers over 10 feet deep are considered extra depth and require additional working space and/or right-of-way.
  • Sewers over 15 feet deep require substantially more construction space and/or right-of-way. Space requirements increase with increasing depth and ground slope. Sewers over 20 feet deep create major problems in both construction and maintenance and will not be allowed unless absolutely necessary.
  • Placing the sewers in the streets is preferable to placement in the rear of lots.
  • Sewers are to be located to minimize disruption to environmental features. By necessity, outfall sewers are located along drainage courses, where streams, wetlands, tree-save areas, parks and open space areas are likely to be located. The number of stream crossings are to be kept to a minimum and are to be perpendicular to the stream. Wetlands are to be avoided as much as possible. Normally, the ground rises relatively sharply just beyond the floodplain. These slopes are to be avoided.
  • Sewers along streams must be designed to be able to serve both sides of the stream. Therefore, the sewer cannot be placed too far from the stream or too far up the slope. A 25 foot minimum buffer between the stream bank and cleared construction area is to be provided.

3.  Water Loops

A loop is a water main constructed to provide a link between two existing or new water mains. Water loops serve two primary purposes in the distribution system. They provide a second feed to an area to prevent outages resulting from a water main break, and they prevent dead ends in the system. Such dead ends can degrade water quality if there is insufficient demand at the end of the line to keep the water from becoming stagnant and losing its chlorine residual. Water loops which are not included in the applicant's costs are funded by general bonds since they are a system improvement.

When WSSC staff review requests for service extensions, they look to see if a loop is needed based upon the following criteria:When WSSC staff review requests for service extensions, they look to see if a loop is needed based upon the following criteria: 

Situation: Future water quality problem avoidance                                                   
Criteria: 5 feet of main per new unit or 300 feet of main, whichever is greater.

Situation: Known water quality problems
Criteria: 10 feet of main per unit, or 650 feet of main, whichever is greater.

Situation: A 2nd feed for outage avoidance (redundancy)    
Criteria: 5 feet of main per new unit or 300 feet of main, whichever is greater.

If a loop connects two water mains entirely within an applicant's project, or extends outside the applicant's project to solely benefit the project, the loop is shown on the engineering report sketch as a solid line and its cost is included in the applicant's overall project cost analysis. If the loop is required to serve both the applicant's and external properties, then the cost will be apportioned to the applicant's project and the general bond fund (WSSC) in proportion to the number of internal and external protected units respectively. If a loop extends outside the applicant's project for the sole purpose of improving the local water system, it is not included in the applicant's cost analysis and is funded by the general bond fund.

4.  Grinder Pump/Low Pressure Sewerage Systems  

Under this system, each residence is served by an individual Grinder Pump assembly typically installed in a buried tank on the resident's property, which pumps the sewerage through a small diameter pipe to a main in the street. The property owner is responsible for providing maintenance of the on-site system. The WSSC maintains the main in the street and the connection to the property line of the property served.

Grinder pump/low pressure sewerage systems are permitted only when all of the following criteria are satisfied:

  • The extension of gravity service to the property is inconsistent with adopted master land use plans, the County's 10-Year Water and Sewer Plan, or otherwise considered infeasible by the WSSC.
  • The proposed use is for residential property only.
  • The proposed use will not, in the judgement of the WSSC, result in odor or corrosion problems, due to the formation of hydrogen sulfide.

5.  Right-of-Way  

Right-of-way acquisition for water and sewer lines outside of an applicant's property is the responsibility of the WSSC. Negotiation for such rights-of-way is sometimes a major obstacle to timely construction. All rights-of-way through an applicant's property, including those required for future mains, must be provided gratis to the WSSC as a condition of the authorization. Required right-of-way widths for various pipe sizes and conditions are contained in the WSSC Water and Sewer Design Manual.

F.  Unit Cost Factors

Unit prices (cost per foot) for use in Engineering Feasibility Reports are prepared annually by the WSSC's Accounting Division. The cost of extensions include the construction of the water and/or sewer lines, direct WSSC supervisory and material costs, design cost including the review of the consultant or owner prepared plans, right-of-way acquisition, and indirect costs. The basis for each year's prices are the previous year's actual construction cost by pipe size as adjusted for inflation or other variables. The pipe costs do not include special requirements such as tunneling, extra depth sewer, etc. When these special requirements are encountered, the extra costs associated with them are included in the project's costing.

After the unit price is determined, a projected assessment rate is computed based on costs, expected interest rates, and the ratio of expected construction footage to assessment footage. Typically, about 1 l/2 feet of assessment can be expected for each foot of water or sewer mains constructed. This factor is analyzed yearly as a part of the assessment rate setting calculations. Ideally, 2 feet of assessment per foot of main could be attained since property on both sides of a street would be assessed. However, corners, intersections, and unassessable parcels, reduce the actual assessment amount.

Deficit payments, as further explained in Chapter 3, are required when necessary based on the average unit costs and projected assessments. Each project will experience a cost either higher or lower than the projected average. The variation from average is due to site conditions, season, competition, and other factors. Actual assessment rates are, by law, applied uniformly throughout the Sanitary District and are not established project by project. A table of recent Unit Cost Factors is shown in Appendix F.

G.  Front Foot Benefit Assessment

A cost that owners incur for water and sewer main lines abutting their property is referred to as a Front Foot Benefit Assessment. An assessment is levied upon all properties abutting main lines built in a street, road, lane, alley or right-of-way. This charge is levied for the purpose of repaying funds borrowed for water and sewer main construction. This assessment is payable with County property tax bills. Unless paid off earlier, the annual charge will appear on tax bills for the life of the bonds sold to fund construction -- currently 23 years. Rates for every year are different, because they are calculated to recover the construction and bond interest costs incurred for the water and sewer mains constructed during the year. 

1.  Assessment Methodology 

While specific details on benefit assessments can be found in WSSC's Assessment Manual, typical property assessment methods are based on the following:

  • Residential Lot: Square or rectangular shaped lots are assessed for actual frontage at the Subdivision rate. Irregularly shaped lots and cul-de-sac lots, are assessed based on the front footage of normally shaped neighborhood properties. 
  • Multi-Units: Townhouse units are assessed for 50 feet per unit (despite actual frontage) at the Subdivision rate. Apartments are assessed at 20 feet per unit at the first business rate. 
  • Parcels: Parcels of land in an improved or unimproved state, but not recorded as a subdivision lot, are assessed at the three tiered Small Acreage rates, with footage based on abutment. 
  • Business: Businesses are assessed for all frontages at Business rates. Properties used for a single endeavor are assessed at the three tiered Business rates. Properties with two or more businesses are assessed for all frontages at the first Business rate.

The reader should be advised that if there are any conflicts between this manual and the Assessments Manual, the Assessment Manual's interpretation shall prevail.

H.  Additional Costs

Applicants usually only bear the cost for those facilities which are required to serve their project. As an example, if a larger diameter pipe is necessary to serve potential growth in an area of which the applicant's project is only a part, the applicant only pays for what they need in terms of an "equivalent-line" size. If the larger line size needed to serve other properties is program size, the additional cost of the larger line will be included in the applicant's deficit #2. A deficit #2 payment is required if there is insufficient SDC revenue or bond funding to cover the cost of the CIP project.

1.  Items Included in Overall Cost Analysis 

Unusual construction conditions result in additional costs, because they are not included in the derivation of the unit cost factors. Typical cases include:

a.  Extra Depth Sewer: Sewer main excavations greater than 10 feet. 

b.  Pressure Reducing Valve: When a pressure reducing valve is constructed as part of a water main extension.

c.  Storm Drain Precede: Storm drain segments constructed in advance of water and sewer mains add to WSSC's contract cost. This construction must be approved by the Water and Sewer Design Section, and is included in the overall cost analysis only if identified and approved prior to project re-costing (see Chapter 3). Otherwise, it will be a cost entirely borne by the applicant. 

d.  Tunnel (Bore and Jack): When necessary to tunnel under a roadway, railroad, etc., the following cost apportioning applies:

  • 100% - When tunnel is exclusively required for applicant's property and the project is considered a "large development" (more than 30 SFDU's or equivalent commercial flow).
  • 50% - If project is a "large development" but tunnel will serve any other property, 50 percent shares between applicant and WSSC.
  • 50% - If project is a "small development" (30 SFDU or less or equivalent commercial flow) and tunnel is exclusively for applicant. 
  • 25% - If project is a "small development" and tunnel will serve any other property.

This cost will be applied to an "equivalent tunnel size" consistent with the "equivalent line size" methodology which equates pipe payment responsibility to an applicant's site development requirements.

2.  Costs Borne by Applicant 

Existing WSSC facilities sometimes pose problems for new development sites. When a subdivision site layout cannot be modified to avoid WSSC facilities, a cost surcharge is imposed. The surcharge is always payable by an applicant regardless of the deficit or surplus situation. Typical surcharges include:

  • Abandonments: Abandonments of previously constructed Commission facilities. 
  • Relocations: Relocation of previously constructed Commission facilities that do not provide direct service for the new development is considered a surcharge. If the relocated facilities provide direct service their cost will be included in the cost calculations for deficit/surplus determination.
  • Replacement/Relief Mains: Replacement or relief mains required strictly due to the applicant's development scheme are considered a surcharge. All other replacement/relief main costs would be borne by the WSSC. 
  • Assessment Payoff: Existing assessments must be paid off on properties for which multi-unit residential development is proposed, as well as properties, or portions thereof, whose assessments will be suspended due to designation as common ground, outlot, or other exempt status.

I.  Construction By Applicant   

The 1993 legislation which authorized the WSSC to impose the System Development Charge also allowed for developers and others to construct the water and sewer facilities needed for their development, at their expense, subject to WSSC approval. Upon completion of construction the facilities are turned over to the WSSC for service and maintenance. To do this, the applicant must execute a Memorandum of Understanding (MOU) with the WSSC which covers the design and construction of the facilities in accordance with SOP PD-93-06. Under this agreement the applicant must pay all costs incurred by the WSSC for the construction. This would include plan review, supervision and inspection, and other costs incurred by the Commission. If the facilities to be constructed are in the Capital Improvements Program, the applicant will receive credits toward their Systems Development Charge for the eligible cost incurred by the applicant for the design and construction of the facilities in accordance with SOP CUS 94-03.

If the applicant constructs the house connections along with the mains, they will not be required to pay house connection fees. The applicant is still required to file connection applications. Where the development is served directly by mains constructed by an applicant, the development would not be subject to a front foot benefit assessment since there is no expense to the WSSC to provide service.

J.  Dry Water and Sewer Systems

In accordance with the Montgomery County and Prince George's County Ten-Year Plans, all subdivisions which are to be initially developed on interim individual systems shall also construct the community systems. This includes the connections from the lateral main to the property lines and hookups between the property line to the immediate vicinity of the structure; however, the structure shall not connect to the system.

The applicant would be required to construct, at their own expense, the "dry" system in accordance with plans and specifications approved by WSSC, and must pay all costs incurred by the Commission relating to the project. The system would be turned over to the Commission upon completion of construction. Properties abutted by the "dry" system would not be subject to a front foot benefit assessment. 

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Chapter 3:  Engineering Feasibility Report 

A.  Overview 

An Engineering Feasibility Report determines the water and sewer mains and facilities which must be constructed to provide the requested service. It also estimates the costs of those mains and the assessment yield which will be generated by their construction, and lists the conditions which the applicant must comply with in order for service to be provided. A sample report is shown in Appendix C. 

B.  Report Preparation

The first step in the preparation of the report is to review WSSC records to determine the nearest existing water and/or sewer mains to serve the development. The route decided upon would be based on sound engineering practice. A review of WSSC records should also be made to determine if any authorized projects are in the area. In designing the proposed extensions, the best information currently available should be used, such as established street grades, preliminary grading plans, and any prior planning information available. M-NCP&PC 200-foot topography sheets are useful for off-site design in undeveloped areas. The design of the proposed extensions in the report is a preliminary design and need not show all details except where it directly relates to the cost of the extensions, or to address a specific point mentioned in the report. Examples would be the cost of a pressure reducing valve or mains to be abandoned. Main sizing is not required for the initial layout of the proposed mains. The mains will be sized by the Commission's Water Resources Planning Section as part of the report review process.

1.  Report Sketch 

An integral part of a report is the sketch. The project is to be shown on a sketch at 1" = 200' scale. The base for the sketch shall be a black line print of the Property Assessment Section 200-foot sheets, which show existing water and sewer mains on the same sheet. If the sketch requires more than one 200-foot sheet, the sheets must be attached together. Off-site extensions may be shown on a separate sketch with reduced scale. The sketch shall show all the information identified in the Sketch Color Coding Section of this chapter and include a legend depicting the color code. Relevant field observations should also be shown. A sample sketch is shown in the report in Appendix C.  

2.  Sketch Color Coding  

The following factors apply to gravity sewers. Grinder pump systems are addressed later in this section. If service will require a pumping station and force main, the applicant's engineer should consult with the WSSC.

Sample Sketch

3.  Environmental Inventory  

In order to properly review and assess possible environmental impacts and determine what environemental permits will be required, the following information as shown on the preliminary plan of subdivision must be provided if it is applicable to the site to be developed:


Show all steep slopes (>15%).

Forested Areas

Show all woodlands classified by DNR regulations as "Forests" (A Forest Stand Delineation and Natural Resources Inventory will be subsequently needed if a Forest Conservation Approval is required).


Show delineation of tidal and non-tidal wetlands and their buffers as defined by MDE regulations. 


Show waterways that appear on USGS quadrant maps and their flood plain limits, and indicate the drainage area at the points of any stream crossings. 


Identify any "Critical Habitats" or "Natural Heritage Areas" as defined by DNR. 

Critical Areas 

Show the limits of any Chesapeake Bay Critical Areas and their buffers (Prince George's County only). 

Cultural Sites

Identify any historic or archaeological sites as defined by M-NCP&PC or MD Historic Trust. 

Rural/Rustic Rds.

Show any Rural/Rustic roads as identified by Montgomery DOT.


 Show any Special Protection Areas as designated by M-NCP& PC.

Park Lands

Show any M-NCP&PC, State, or Federal parkland to be impacted.

4.  Extension Cost Sheet

After a route and size has been chosen for the extension(s), a cost analysis is then prepared on the standard forms. Cost tabulations are based on the most current UNIT COST FACTORS (Appendix F). Any Equivalent Line Sizing must be shown on the cost sheet to properly account for the applicant's needs. Any additional costs, as explained in Chapter 2, must also be included on the cost sheet. The annual cost and yield are tabulated by part and for the total project showing surpluses or deficits. Where applicable, the costs shall be separated by funding source: General Construction, Water Bonds, Sewer Bonds or construction by applicant.

An explanation of the terms printed along the top of the Extension Cost Sheet follows:

  • The "COST" is the product of multiplying the segment "LENGTH" by the "UNIT COST PER FOOT" of the pipe diameter selected.
  • The "INTEREST COST" is the product of multiplying the "COST" by the appropriate bond "INTEREST COST FACTOR".
  • "INTEREST COST" and "COST" are added; this sum is then divided by the appropriate number of "Bond Years" to derive the "ANNUAL COST".
  • The "TOTAL YIELD" is the sum of the various classifications of front footages to be assessed multiplied by the appropriate assessment rates.
  • The difference between the "TOTAL YIELD" and the "ANNUAL COST" produces the "ANNUAL SURPLUS or (DEFICIT)".

5.  Field Review 

Field review for a proposed project should be done after the water and/or sewer route alignment is tentatively established. Important field reviewer's observations and notations might include: the location of existing buildings, storm drains, tree areas, existing paving, deep basements, as well as any other information which might have economic, engineering, or environmental implications to the extension.  

6.  Property Owner Notification 

If the extensions proposed in a report will cause property owners other than the applicant to be assessed, those owners are sent a letter by WSSC staff which informs them of the pending construction and the financial implications. For properties which have existing buildings on them, a post card questionnaire is also included to ascertain whether the owners desire service or not. The results of this canvassing are summarized in the report and noted on the report sketch. Should any property owner submit a written objection to the proposed extension, the project must be referred to the full Commission for decision at one of its regularly scheduled meetings. 

C.  Deficit Payment Calculations  

If the ANNUAL YIELD equals or exceeds the ANNUAL COST, the project has a SURPLUS. If costs exceed the yield, then the project has a DEFICIT. A surplus in any of the project's parts offsets a deficit in another part. If a project has an overall deficit, a Deficit Payment will be required of the applicant as a condition of the authorization. Explanations and examples of deficit calculations follow.

1.  Interior Deficits 

An Interior Deficit applies only to the cost/yield comparison for water/sewer mains within a new subdivision. An interior deficit is "capitalized" i.e., the Annual Deficit is divided by the appropriate Capital Recovery Factor to determine the required Deficit Payment. Capitalization converts the annual deficit into an equivalent present value amount which is payable prior to construction. This payment brings an authorization into a break-even situation. Appendix G shows an example of this break-even situation.

  • Lots 1-9 to be assessed based on the rate associated with the existing mains.
  • Lots 10-18 assessable from new construction.
  • Resultant deficit is capitalized since new mains are within perimeter of new subdivision. 
  • View Lot 1-9 and Lots 10-18!

2.  Exterior Deficits 

View Exterior Deficits (Includes sub items a,b,c and d)

a.  Non-Assessable Property
b.  Existing Development

  • Served by Water and Sewer
  • Served by Well and Septic

c. Potential Development    

  • Right-of-Way
  • Stream Valley
  • Roadway

d.  Service Area 5 and 6 

3.  Interior-Exterior Deficits 

Click here to view Interior-Exterior Deficits

4.  Health Hazard Subsidy  

Click here to view Health Hazard Subsidy

5.  Miscellaneous Cases  

a.  Applicant's Property Not Assessable: Except as provided in paragraph B, below, If the property to be served by a proposed extension is not assessable (due to being assessed previously, governmental ownership, etc.), and no other assessment will be generated by the extension, the construction of the proposed extensions will be done by the WSSC at the applicant's expense. Prior to bid advertisement, the applicant will be required to pay a deposit to cover construction, engineering, overhead and other contingencies. After construction is completed, any difference between actual cost and the deposit will be reconciled. 

b.  Applicant for Service is Tax Exempt: Where an applicant for service is a tax exempt oganization under Section 501 of the Internal Revenue Code which leases property owned by a governmental entity, and where the application for service is premised upon a documented septic system failure or inadequacy, the extension project may be costed pursuant to Sections C.1, 2 or 3 of this Chapter, as appropriate.

D.  Recosting of Projects

Click here to view Recosting of Projects (Includes items D, E, and F)

  1. Single Authorization
  2. Multi-Part Authorization

E.  Merging of Authorizations

Click here to view Merging of Authorizations (Includes items D, E, and F)

F.  Consultant Prepared Rules   

Click here to view Consultant Prepared Rules (Includes items D, E, and F)

  1. First Submission 
  2. Second Submission

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Chapter 4:  Connections and On-Site Systems 

A. Unimproved Area Residential Connections 

When new mainline projects are built, lateral service connection pipes are simultaneously built for each lot or house of a new subdivision as well as to each property along the route of the pipeline. In the latter case, connections are built as long as connection application forms are submitted by property owners and the property is in the right service area. As a condition of an authorization, builders and developers must file a connection application form for all recorded lots or buildings of their project. A copy of the connection application form is included at the end of this chapter.

B.  Improved Area Connections

When a mainline abuts property, an authorization is not required, and service can be provided in a more timely manner. Connection service still requires: being in the correct service area category; a recorded plat; design and approval of on-site plans; and line size adequacy. 

C.  Residential Connection Fee Payment

Connection fees for residential properties must be paid in full at the time of application for connections. A payment plan to defer or amortize the connection charge over a period of years as part of the annual tax bill is available only for connections to serve owner occupied dwellings with Health Department certified failed well or septic systems. 

D.  Commercial Connection Fee Payment

All non-residential connection charges, including those for apartment buildings, must be paid at the time of application. This is true whether the connection is built concurrent with mainline work, or built separately when mains already exist to serve the property.

  • A non-residential complex composed of two or more buildings on a single tract of land may be served by a single connection. A single connection can be approved if the owner enters into a legal agreement (covenant) with WSSC. The agreement compels the owner to bear the future expense to retrofit individual service connections prior to the sale or subdivision of any portion of the multi-building complex. Such an agreement is recorded with the land records.

E.  On-Site Systems 

Connection service for certain types of development entail special on-site construction requirements.

1.  Grinder Pump Service

Grinder pump installation and future maintenance is the responsibility of the homeowner. Grinder pump installations must be done by a WSSC registered master plumber under the authority of a plumbing permit. Electrical work must be performed by a qualified electrician under a county electrical permit.

2.  Large On-Site Piping Schemes  

On-site plans must be submitted for review and approval if one or more of the following conditions exist

  • water lines greater than 2-inches in diameter
  • sewer lines greater than 4-inches in diameter
  • sewer lines will require manholes; or
  • water/sewer systems have special conditions (e.g. force mains, fire sprinklers, fire hydrants, pretreatment of waste).

3. Industrial Discharge Permits

WSSC imposes pre-treatment requirements on certain businesses/processes. Examples include:







Food processing  








Power Plants


F.  On-Site Plans and Permits   

Unless waived (by the Code Enforcement Section), on-sites associated with new or enlarged buildings require special on-site construction permit. On-site plan design must be certified by a Registered Professional Engineer licensed in the State of Maryland. Such plans must be submitted to the Service Applications and Records Section for review in advance of construction. Once on-site fee payment is made, and three prints of the plans with engineer's seal affixed are submitted, a project number is assigned. Both plans and design must conform to WSSC rules and regulations. In advance of construction, the permittee/on-site contractor must submit: (1) application and payment of connection fees; (2) a complete list of materials to be installed; and (3) the name of the engineer who will certify construction conformity to WSSC policies and the approved plans. Plumbing hookup inspections are not issued until the on-site system has been accepted by the Construction Bureau. 

G.  Fire Sprinkler/Surveillance Systems

Residential and commercial fire sprinkler system installations must be constructed in accordance with WSSC Plumbing and County Fire Marshall standards. Fire hydrant or sprinkler system flow can be either: (1) "surveillance detector monitoring" installed directly on each fire hydrant lead or sprinkler system or; (2) by installing an alarm-signaling device on a looped fire line inside the structure. A surveillance company must be engaged to remotely monitor unmetered fire systems, with the agreement between the owner and the surveillance company filed with the WSSC (Service Applications and Records Section).

H.  Meters and Meter Setting    

1.  Small Meters 

To avoid freezing or vandalism, a meter is normally installed inside a heated building. WSSC crews install meters smaller than 1-1/2 inches while the plumber installs all necessary meter hardware. Each small meter must be wired for a remote reading device. These devices must be located in an unobstructed position for accessibility.

2.  Large Meters 

Larger inside meters are installed by registered plumbers. If a meter cannot be installed inside a building in ample space, an above-ground structure must be built to WSSC specifications at the applicant's expense. Only in extraordinary circumstances are outside, in ground meter vaults approved. 

3.  Submeters  

Water consumption and sewer usage charges for WSSC customers are based upon the volume of metered water use. Recognizing that some water use does not result in a discharge into the sewerage system (lawns, air conditioning units, gardening, swimming pools, etc.), WSSC has provisions for a submeter. Like the master meter, the submeter belongs to the WSSC, but it measures only water that does not discharge into the sewerage system. With the submeter arrangement the customer is only charged for sewer usage on the "domestic" portion of the total consumption.

I.  WSSC Acquisition of On-Site Systems 

The owner(s) of a private on-site water and/or sewer system may request that the WSSC acquire all or parts of the system, and assume responsibility for future operation and maintenance of the system. If WSSC agrees to the acquisition request, the applicant is required to evaluate the system, complete all necessary system upgrades, and reimburse WSSC for its costs to review the applicant's evaluation and upgrade of the system. For on-site residential systems, WSSC will, if requested by the owner, evaluate and upgrade the system. Such applicants are required to pay for WSSC's system evaluation and upgrade costs over a number of years by agreeing to an annual property assessment. WSSC will consider acquisition of all or part of an on-site system if all of the following apply:

  • The system has been in service more than five years.
  • The building(s) or property served is or will be under separate ownership as specified by the WSSD "Plumbing and Gas Fitting Regulations".
  • Sewer line sizes are 6-inches or greater in diameter and water lines are 4-inch diameter or greater.
  • Water conservation will be achieved by separate metering.
  • Customer health and welfare are an issue.

To begin the process, a written request for WSSC takeover must be submitted to the Water/Sewer Reports Section which outlines why the WSSC should assume maintenance responsibility. The request must be accompanied by: record plat; site plans showing the existing facilities and structures served; vicinity maps; and plans which highlight the specific segments proposed for WSSC takeover. Details and requirements of the process are contained in WSSC Standard Procedure #PD 94-03 -- WSSC ACQUISITION OF ON-SITE WATER/SEWER SYSTEMS.

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Chapter 5:  Post-Authorization Staging 

A. Project Design

Progression from authorization to construction of a project is not automatic! The applicant must contact the WSSC and make arrangements for design. The Water and Sewer Design Section handles extensions, and the Project Management Section handles facilities. A "pre-design meeting" will be held at which time design and review needs and requirements are discussed and a schedule can be established. Appendix H lists some of the tasks and time frames involved in scheduling. The design can be performed by either WSSC or the applicant, and the construction can be performed by either WSSC or the applicant in accordance with the authorization. Construction by the applicant requires entering into a Memorandum of Understanding (MOU) with the Commission. A brief explanation of these options follows. For a more detailed explanation, contact the design section noted above.

B.  Applicant Designed Plans

For most development work, the applicant engages a consulting engineer to prepare the design. Prior to the initiation of design, the applicant is to submit to WSSC the name of the firm that will perform the design. Upon completion and approval, the plans become the property of the WSSC. 

C.  WSSC Designed Plans 

Prior to the initiation of design by WSSC, the applicant must enter into an Engineering Agreement. Conditions that must be satisfied may include but not be limited to the staking of property lines and street locations, the provision of approved street grades, certification of the actual grading, an approved Soil Conservation District sediment control plan, and approved storm drainage and stormwater management plans. By entering into an Engineering Agreement, the applicant may defer grading of streets, payment of house connection fees, and the Deficit Payment until after the design is completed. To do this the applicant makes an engineering deposit to cover the estimated cost of plan preparation, and agrees to pay all actual WSSC costs for plan preparation should the applicant not proceed with the project. If the project does proceed, the engineering deposit is refunded to the applicant.  

D.  Projects Built by WSSC

After design of the project, the WSSC will obtain the necessary construction permits (refer to Appendix I for permit requirements). Once all the conditions of authorization are satisfied, the WSSC bids the project for construction. During construction, WSSC will inspect the work of the contractor to ensure adherence to WSSC's standards and specifications. Upon completion of the construction, the system will be released for service. 

E.  Projects built by the Applicant Under a Memorandum of Understanding

After design of the project, the applicant must obtain the necessary construction permits and engage a contractor for construction. When the conditions of authorization are met, and the Memorandum of Understanding is executed, the WSSC will provide inspection to ensure adherence to WSSC's standards and specifications. Completion of construction, rights-of-way on the applicant's property, an account settlement, and a maintenance bond are some of the items that must be provided prior to the release of the system for service. The MOU will list all project requirements.  

F.  Plumbing Inspections 

All on-site work requires plumbing inspection. Except for meter setting by WSSC Maintenance Crews, plumbing inspections can usually be scheduled a day after a phone request is made. Once a meter is set, a final plumbing inspection can then be arranged. The final plumbing inspection satisfies a prime criterion for a County Use and Occupancy Permit. 

G.  Water/Sewer Billing 

After occupancy, residential customer and smaller commercial users will be billed quarterly for water and sewer usage based on metered water consumption. Heavy users are billed on a monthly basis. The WSSC has a conservation-oriented sliding rate billing system for water consumption and sewer usage. The rates paid per 1,000 gallons of usage depends on the Average Daily Consumption (ADC) during each billing period. 


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Click here to view Appendices A-J 

A.  Sub-District Fees 
B.  Water and Sewer Service Staging
C.  Engineering Feasibility Report 
D.  Delegation of Authority 
E.  Water and Sewer Authorization Conditions
F.  Unit Cost Factors 
G.  Capital Recovery Factor 
H.  Project Design and Construction Scheduling  
I.  Construction Permit Requirements
J.  Fees and Charges

Authority Clause

The General Counsel certifies that the statutory authority for the adoption of this manual is Article 29, Sections 9-101,1-102, 1-202, 3-101, 3-102, 3-103, 3-104, 3-105, 3-106, 4-101, 4-107, 4-110, 5-101, 5-102, 5-103, 5-104, 5-106, 5-107, 6-101, 6-102, 6-103, 6-104, 6-109, 6-113, 7-101, 7-102, 7-103, 7-104, 7-105, 7-106, 7-107, 8-101 & 8-102 of the Annotated Code of Maryland.

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