City and EPA officials announced yesterday that bacteria levels in D.C. tap water exceeded federal health standards this month for the first time since 1996. However, they claim most people are not at risk.
The rise in bacteria was detected in routine testing this month. It may be the result of using a new water treatment chemical to reduce lead levels in the water at thousands of city homes, officials said during a news conference.
The chemical, orthophosphate, may have flaked off a layer of rust and bacteria inside water pipes, they explained.
Officials from the D.C. Water and Sewer Authority, the EPA and the city Health Department said tests did not find specific disease-causing bacteria. Therefore, they recommended that only people in certain at-risk groups people with weak immune systems, some elderly people and infants consult doctors about whether to boil water before drinking it.
So far, testing has not found any bacteria problems in Northern Virginia, where hundreds of thousands of residents drink water from the same treatment plants serving the District. The areas served in Northern Virginia include Arlington County, Falls Church, parts of Fairfax County that receive water from Falls Church, and the city of Vienna.
Rick Rogers, the chief of the EPA's regional water branch, said the city's high bacteria levels "could go on for a few months."
Rogers said it is "not an option" to stop using orthophosphate. EPA officials claim they are confident the chemical will bring down lead levels, though it could take a year to do so.
Last month, when EPA approved the use of orthophosphate city-wide after a three-month trial in part of the Northwest, it ordered WASA to conduct an aggressive flushing program to wash bacteria from the pipes.
However, EPA agreed that the flushing could begin after the Army Corps of Engineers, which operates the two city treatment plans, began adding orthophosphate.
Rogers said "unidirectional flushing," which is more forceful than simply opening hydrants to clear the system, "did not happen as early as we had hoped." But he said "in terms of this issue, it wouldn't have made any difference."
WASA began the flushing this month. General Manager Jerry N. Johnson said the utility will finish before the arrival of freezing weather. He said WASA will add more crews next week to expand the work, with 10 to 15 three-person crews on the job instead of the current eight or nine.