Sewer overflows were reported at two Washington area pumping stations due to excessive rains this week, but so far have not affected the safety of drinking water, officials said Thursday.
An overflow of raw sewage mixed with water started mid-afternoon Wednesday at the Fort Washington Forest Wastewater Pumping Station in Prince George’s County and continued through the late morning Thursday, said Kira Calm Lewis, a spokeswoman for the Washington Suburban Sanitary Commission.
A second overflow of diluted sewage at the Broad Creek Wastewater Pumping Station in Fort Washington on Wednesday also continued through Thursday morning. Overflows are common in the Washington region, and can threaten drinking water. Several jurisdictions are under court order to limit them.
Lewis said the area’s drinking water is safe and so far not threatened by the current overflows. She said the Maryland Department of the Environment was notified of the two overflows.
WSSC said it was too early to estimate the volume of the overflows. The Broad Creek station overflowed after its capacity of 37 million gallons per day capacity was exceeded, and the Fort Washington pumping station spilled over after flows topped its capacity of 200,000 gallons per day.
D.C. Water and Sewer Authority officials said their system likely overflowed during the heavy rains, but they issued no report. When it cannot handle flows, the District’s sewer system is designed to release raw sewage from businesses and homes, mixed with rain runoff, into the nearest body of water. Officials said that option is preferred over allowing diluted sewage to back up into sinks, tubs and toilets.
Fairfax County officials said there were no reported problems in their sewer system. Arlington and Prince William county officials did not return phone calls early Thursday asking about conditions in their systems.
The current reported sewage overflows are much smaller than those caused by the deluge of Hurricane Irene about a week ago. D.C. Water officials estimated that at least 200 million gallons of rain mixed with raw sewage overwhelmed pumping stations and poured into waterways around the city.
The Maryland Department of the Environment reported that the storm caused the release of millions of gallons of waste into streams and rivers that flow into the Chesapeake Bay.
Wastewater combined with rain overflowed Baltimore County pumping stations a dozen times, the agency reported, and wastewater plants at several towns on the Maryland Eastern Shore also overflowed as a result of the hurricane.
Some 4.3 million gallons of diluted sewage overflowed in Upper Marlboro for 14 hours during the storm; about 13.7 million gallons overflowed at an Accokeek wastewater treatment plant; and 2 million more gallons of diluted sewage overflowed at the Broad Creek station for nearly 12 hours.
“Potentially harmful substances may also be present in these discharges,” according to D.C. Water’s Web site. “For larger rainfalls, greater than 1 inch . . . effects . . . on water quality can last up to three days.”