Frequently Asked Questions - Discolored Water

Why is the water discolored?

Due to the severe weather and heavy rains the past several weeks, WSSC water quality experts have seen a dramatic increase in organic material (decayed leaves, river grasses, trees, vegetation, etc.) and manganese coming into our Potomac Water Filtration Plant intake. Both naturally occur in waterways.

This plant uses chlorine to disinfect the water and make it safe for drinking. Chlorine also controls manganese levels to prevent discoloration. However, chlorine also reacts with organic material to form disinfection byproducts. Disinfection byproducts are a public health concern, and as such, are highly regulated by the U.S. EPA. Levels cannot exceed the EPA limit as an annual average. Fortunately, WSSC is well below the EPA limit.

To ensure we keep the level of disinfection byproducts well below the EPA limit, we must slightly reduce the level of chlorine when we experience an increase in organic material. While we still add enough to disinfect the water and kill all bacteria, a slightly lower chlorine level allows manganese levels to increase in our finished water – causing the discoloration

Has this area experienced that much rain?

Yes. The Potomac River is flowing high right now – especially for August. For the month of July, 5.37 inches of rain have accumulated at Reagan National Airport, 2.57 inches above normal. A late July winter-like storm brought nearly 4 inches of rain to Reagan National Airport. In the course of about 24 hours in late July, the airport received the equivalent of an average month’s supply of rain (3.73 inches). A few months ago, our two reservoirs on the Patuxent River were about half full. Now they are both completely full thanks to all this rain.

Is WSSC water safe for everyone to drink, even those with health issues?

Health standards are made for the general population. People with certain medical conditions or compromised immune capacity, such as infants, pregnant women or cancer patients, should ask their doctor if it is okay to drink tap water. We know our water is safe for vast majority of our customers, but because we are not medical professionals, we want you to take any precautions as you would when you consume food.

Why doesn’t chlorine solve the discoloration?

The Potomac Water Filtration Plant uses chlorine to disinfect the water and make it safe for drinking. Chlorine also controls manganese levels to prevent discoloration. However, chlorine also reacts with organic material to form disinfection byproducts. Disinfection byproducts are a public health concern, and as such, are highly regulated by the U.S. EPA. Levels cannot exceed the EPA limit as an annual average. Fortunately, WSSC is well below the EPA limit.

What's a disinfection byproduct?

It is a chemical produced as a results of disinfection process. There are only miniscule amounts present in the source water. But if we disinfect, and if we are not careful, it can potentially become a health issue.

To ensure WSSC keeps the level of disinfection byproducts well below the EPA limit, we must slightly reduce the level of chlorine when we experience an increase in organic material. While we still add enough to disinfect the water and kill all bacteria, a slightly lower chlorine level allows manganese levels to increase in our finished water – causing the discoloration.

What are your current disinfection byproducts levels?

There are two disinfection byproducts formed when chlorine reacts with naturally-occurring organic material: Haloacetic Acids and Trihalomethanes. The EPA limit (annual average) for Haloacetic Acids is 60 parts per billion (ppb) and WSSC’s August annual average level is 48.8 ppb. The EPA limit for Trihalomethanes is 80 ppb and WSSC’s August annual average level is 64.8 ppb.

When did you reduce chlorine levels?

August 8, 2017

Do lower chlorine levels jeopardize public safety?

No. We are still adding enough chlorine to the water to kill any bacteria and make the water safe. We would never compromise public safety, which is exactly why we made the decision to decrease chlorine to ensure we stayed well below the EPA levels for disinfection byproducts.

Are reduced chlorine levels still strong enough to keep the water safe?

Yes. We continuously test chlorine levels throughout our distribution system. We are still adding enough to keep the water safe for all our customers.

Are the manganese levels in WSSC water a health concern?

No. Manganese at the levels we are seeing are not a health hazard and it is not regulated by the EPA as a drinking water contaminant. In fact, EPA considers manganese a secondary maximum contaminant level for aesthetic reasons only. The EPA level for aesthetics is 0.05 milligrams per liter (mg/l). And our current manganese levels found in homes throughout our service area are around 0.01 to 0.03 mg/l. Although below this aesthetic level set by EPA, it can still cause discoloration.

Are you testing more frequently since August 8?

Yes. We are monitoring for disinfection byproducts more frequently (from biweekly to weekly) throughout both counties due to the high levels of organic material. Additionally, we are monitoring for manganese four times as often at our Potomac Plant and three times more frequently from our customers (9 samples per week to 27 samples per week). We are conducting an average of 100 tests daily.

What have been the test results so far? Have any results come back unsafe?

When a customer calls for a water quality test, we will test for manganese, other metals, chlorine, bacteria and a full list of all EPA water contaminants. All water quality test results have met the Safe Drinking Water Act standards – safe to drink. Our current manganese levels are around 0.01 to 0.03 mg/l, which is below the EPA aesthetic level of 0.05 mg/l.

Why can’t WSSC use another disinfection method?

Both our water filtration plants – Potomac and Patuxent – use chlorine. It is the best disinfection for us because it is strong and can last longer in our extensive water distribution system. Our water distribution system is much larger than other neighboring utilities and we need a stronger disinfectant. Chlorine is the best choice for us.

You will test water from customers’ homes?

Yes. Customers can call our laboratory at 301-206-7575 if they are ever concerned about water quality and we will test the water for free.

Would you allow children to bath / brush their teeth with this discolored water?

This water is safe for drinking, bathing, brushing teeth, providing to pets, etc. We do caution customers not to run their laundry if they have discolored water as it may stain clothes. We are offering our customers free Rit Rust Remover. Please email us at communications@wsscwater.com and we will mail some out.

Where are you seeing the most complaints?

WSSC’s Potomac Plant serves about 75% of our 1.8 million customers – from northern Montgomery County to Southern Prince George’s County. Most of the complaints are coming from Montgomery County areas like Silver Spring, Chevy Chase, Bethesda, Gaithersburg… but we are also receiving complaints from Fort Washington, Oxon Hill and Suitland in Prince George’s County.

Why aren’t the other utilities that use Potomac River as their source water seeing discoloration?

Both Fairfax and the Washington Aqueduct draw from the Potomac River and both are seeing higher levels of naturally occurring organic material. However, they both use different disinfection methods – they don’t use chlorine – and therefore they can control manganese levels to prevent discoloration.

Are WSSC customers served by the Patuxent plant experiencing discolored water?

No. This plant draws water from two reservoirs and they are not impacted by the severe weather like the Potomac River. Organic material settles to the bottom of these reservoirs – away from the intake.

When will this discoloration issue end for customers?

We are hopeful that the severe weather will subside and the organic material in the Potomac River will decrease. When it does, we will increase the chlorine levels to resolve the discoloration.

If the severe weather continues, will it get worse?

Not in terms of the discoloration, but we fully expect the discolored water complaints to increase impacting more WSSC customers.

What can customers do?

If customers are experiencing discolored water, please call us at: 301-206-4002 or email at: emergencycallcenter@wsscwater.com.  We want to hear from our customers so we can better track this issue. We also ask for our customers’ patience. Flushing their water lines will not help in this situation as the discoloration is coming from the plant. Again, we apologize. We are offering our customers free Rit Rust Remover. Please email us at communications@wsscwater.com and we will mail some out.

Is WSSC offering refunds?

If a customer would like to file a claim because the discoloration permanently stained laundry – or for any reason – they can always call our Claims office at: 301-206-7095 or www.wsscwater.com/claims.

Have claims been filed?

Yes, we have received a handful of claims related to stained laundry.

Does WSSC have a discolored water problem – outside this event?

WSSC has an extensive water distribution system – more than 5,600 miles of pipes. With this vast network of pipes serving 1.8 million customers, we do receive discolored water complaints every month due to broken mains, water main work, extreme use of water during fires and other operational issues that impact the flow of water. We usually see around 100 to 200 discolored water complaints per month. Since we made the treatment change on August 8, we have seen a dramatic increase – more than 800 discolored water complaints.

Has WSSC experienced this level of discolored water complaints before.

Yes. Back in 2015 our customers experienced discolored water caused by a very high spike of manganese coming after snowmelt coupled with historically high chloride in the river wreaking havoc on old cast iron pipes. We suspect both happened as a result of road salt application followed by snowmelt runoff. That event lasted for several months in the winter/spring of 2015.

Should people be worried that we have a Flint Michigan situation?

Absolutely not. This is an aesthetic issue caused by a slight increase in manganese levels in finished water. Flint was dealing with lead in the water caused when a new water supply source corroded the lead pipes in their distribution system. Plus, WSSC does not have lead in its water pipes. Again, this is an aesthetic issue.

Have the local health departments of state weighed in on this issue?

Yes. We work closely with both local health departments and the Maryland Department of the Environment (MDE). Both health departments stood with us at our press briefing on August 14, 2017, to reassure the public that this is an aesthetic issue, not a public health issue. MDE also issued a statement to reassure customers that we are meeting all requirements under the Safe Drinking Water Act.  

How can customers call to contact WSSC?

Report discolored water: 301-206-4002 or emergencycallcenter@wsscwater.com

Claim: 301-206-7095 or online at: wsscwater.com/claims

Rit Rust Remover: communications@wsscwater.com