WSSC Details Cause of Discolored Water

Water Quality Experts and Health Officials Emphasize Water is Safe Despite Discoloration

| News Release



LAUREL, Md. – August 14, 2017: Speaking along the banks of the Potomac River, the source of drinking water for the majority of WSSC’s 1.8 million customers, WSSC General Manager and CEO Carla A. Reid today joined the water utility’s Director of Production J.C. Langley, Deputy Heath Officer for the Montgomery County Department of Health and Human Services Mark Hodge, and WSSC water quality experts to detail the cause of discolored water impacting customers in Montgomery and Prince George’s counties. Since the beginning of August, WSSC has received more than 700 discolored water complaints – a sharp increase from the 200 to 300 complaints each month during the spring. WSSC performs more than 100 water quality tests every day, and all current test results indicate that the water is safe.

“Our number one goal is public health and I want all our customers to know that WSSC water is safe,” said Reid. “But from an aesthetic standpoint, the water is unacceptable and I sincerely apologize to our customers impacted by this discolored water. Our customers should not have to think twice about their drinking water when they turn on their taps.”

In recent weeks, WSSC water quality experts have noticed an increase in organic material in the Potomac River, which occurs naturally in water, possibly caused by recent severe weather events. Organic material comes from decayed leaves, tree debris and vegetation. Manganese is a natural mineral also found in waterways. The increased levels of manganese in the treated water are causing the discoloration. During the treatment process, WSSC uses chlorine to disinfect the water and control manganese levels to make the water clear and safe for drinking. However, chlorine reacts with organic material to form disinfection byproducts – highly regulated drinking water contaminants by the U.S. Environmental Protection Agency (EPA). Disinfection byproducts are a public health concern. With an increase in organic material this summer, WSSC slightly reduced the levels of chlorine to stay well below the EPA limit for disinfection byproducts. While enough chlorine is present to disinfect the water and kill bacteria, the slightly lower level allows manganese levels to increase in the finished water – causing the discoloration.

Manganese is not a health hazard and is not regulated by the EPA as a drinking water contaminant. EPA considers manganese a secondary contaminant for aesthetic reasons only. The EPA level for manganese, for aesthetic purposes, is 0.05 mg/l. WSSC’s current manganese levels are around 0.01 mg/l to 0.02 mg/l. Although below EPA’s aesthetic level, it can still cause discoloration.

“We will always make decisions that are in the interest of public health and safety,” said WSSC’s Director of Production J.C. Langley. “From a public health standpoint, it is more important to address the naturally-occurring organic material to reduce disinfection byproducts in the water versus the aesthetic issue of manganese. Unfortunately, that means the aesthetic issue of manganese will be around for the next several weeks until river conditions change.”

WSSC will closely monitor Potomac River conditions. As organic material levels decrease, WSSC will adjust chlorine levels again to better control the manganese, thereby improving water aesthetics without increasing the disinfection byproduct levels. WSSC officials believe the discolored water may persist for several weeks and could get worse before it gets better.

“Let me be clear, this is an aesthetic issue not a public health issue,” said Mark Hodge, Deputy Health Officer, Montgomery County Department of Health and Human Services. “I want to commend WSSC for being proactive and transparent in explaining the cause of this aesthetic issue to their customers and for their attention to our residents’ health and wellbeing.”

"Protecting public health by ensuring that drinking water provided by public water systems is safe and meets all standards is a priority for the Maryland Department of the Environment," said Deputy Environment Secretary Horacio Tablada. "As part of its regulatory oversight, the department is working with WSSC as it makes operational adjustments to address changes in the nature of raw water in the Potomac River. The department's most recent review of drinking water sampling data from WSSC shows that the utility is meeting all Safe Drinking Water Act standards."

WSSC’s other treatment plant draws water from two reservoirs along the Patuxent River, which are unaffected by the changes in the Potomac River. Customers receiving their water from the Patuxent Water Filtration Plant are not experiencing this discolored water issue. This includes areas in both Montgomery and Prince George’s counties in/around Laurel.

"Prince George’s County residents may notice discolored water for areas served by the Potomac Water Filtration Plant. The water is confirmed to be safe for consumption and normal daily use. The water has been tested and only presents an aesthetic difference and no changes to the water quality or safety,” said Pamela Creekmur, Prince George's County Health Department. 

Customer Information:

WSSC Water is the proud provider of safe, seamless and satisfying water services, making the essential possible every day for our neighbors in Montgomery and Prince George’s counties. We work to deliver our best because it’s what our customers expect and deserve.

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