Recent tests of drinking water in several dozen District homes show encouraging declines in lead levels, a sign that a new chemical treatment begun in August is having an impact, D.C. Water and Sewer Authority General Manager Jerry N. Johnson said yesterday.
Johnson revealed the latest test results at a congressional hearing that also featured sharp criticism of the U.S. Environmental Protection Agency, which this week proposed tighter federal drinking-water regulations. D.C. Del. Eleanor Holmes Norton (D) and witnesses at the House Government Reform Committee hearing said the EPA's recommendations should be broader.
High lead levels in city drinking water since 2002 have triggered federal requirements for the utility to issue public warnings and undertake a lead-line replacement program. To reduce the levels, water treatment officials are adding an orthophosphate chemical to create a protective lining inside pipes so they do not leach lead into the water.
Federally required water testing in 51 D.C. homes since last month found only four had lead readings above 15 parts per billion, the level at which certain federal requirements are triggered. Ten homes where lead levels were above the standard last year fell below it in the most recent tests. The remaining 37 homes were below the standard last year or had not been tested before.
The EPA rule says that if more than 10 percent of homes exceed 15 parts per billion, the utility must inform customers and replace some lead pipes. If the promising test results continue through December, officials could lift a health advisory urging residents to flush out or filter their water before drinking it. Johnson said he was optimistic but not ready to declare victory.
"The numbers are moving dramatically down," Johnson said. "It appears the chemical addition is working."
Erik D. Olson, a Natural Resources Defense Council lawyer who is a critic of WASA, said yesterday that he is encouraged by the new numbers, although he wants to see more details about the tests to be sure they reflect true conditions.
The disclosure early last year of excessive lead levels in thousands of D.C. homes prompted criticism of WASA for its delay in telling the public and of the EPA for lack of more stringent oversight of the utility. Since then, the utility has signed a detailed consent order with the EPA that lays out dozens of operating requirements.
On Monday, responding to lessons learned from the D.C. situation, the EPA proposed the first health-related changes in more than a decade to the Lead and Copper Rule. Norton criticized the EPA at the hearing for not offering broader revisions to regulations on lead, which can stunt development in fetuses, infants and toddlers if ingested. A year after the District's problems came to light, "something more significant is required," she said.
The proposed changes "are not the end of the story," Benjamin H. Grumbles, EPA's assistant administrator for water, told Norton, promising that more changes will be offered. "They will help cure part of the problem."
He said the changes will add up to a "significant upgrade" of the rule governing lead in drinking water, though EPA officials say the rule is fundamentally sound. He also promised that the EPA would significantly revise its instructions to schools on drinking-water safety by the end of the year.
WASA also announced yesterday that the Army Corps of Engineers, which operates the city's treatment plants, would cancel this year's annual spring switch to chlorine as a temporary disinfectant.
Johnson said water-quality experts advised that the benefits of keeping the water chemistry stable to allow orthophosphate to work are more important than the disinfecting benefits of chlorine.
The treatment plants have used chlorine for a few weeks since 2002 to provide supplemental disinfection.
Johnson said his utility's expanded flushing program and other improved maintenance will compensate for that.
Last year, lead levels in city water decreased markedly while chlorine was being used, providing strong support for the theory that the lead problem was triggered by the switch from chlorine to chloramines as a disinfectant in 2002.
The decision not to use chlorine this year also affects Northern Virginia users of the Army Corps of Engineers plants, where lead readings have been below the federal standard.