Lead contamination in Washington, D.C., drinking water

2001–2004: Initial reports of elevated lead

In 2001, over half of water samples from 53 D.C.-area homes exceeded the EPA's Lead and Copper Rule action level of 15 parts per billion. Lead disrupts development in fetuses, babies, and young children, and can cause kidney problems and high blood pressure in adults. The rule does not assume a safe exposure level but sets 15 ppb as a trigger for utility action.

Lead enters water from lead service lines, lead-based solder joints, and lead fixtures. Based on these findings, WASA was required to notify the public and begin replacing lead service lines. The first media coverage came in late 2002, when the Washington City Paper reported on a home with water testing six to 18 times the EPA action level.

WASA found that homes with lead service lines averaged five times the EPA limit over a year. The EPA scientist overseeing D.C.'s water suggested drought might have raised alkalinity in the Potomac River, altering pH. WASA was then required to replace seven percent of the district's lead service lines annually until levels dropped below 0.015 milligrams per liter. At that time, about 23,000 WASA customers had lead service lines.

In March 2003, Marc Edwards, while researching pinhole leaks in copper pipes funded by WASA, tested water in one home. His meter, which could read up to 140 ppb, was pegged even after diluting the sample to ten percent, indicating at least 1,250 ppb of lead. Edwards stated that some of the water would have to be classified as hazardous waste.

2004: Washington Post

The Washington Post ran a front-page article on January 31, 2004, titled "Water in D.C. Exceeds EPA Lead Limit." Reporter David Nakamura was contacted by a homeowner whose water had been tested by WASA. Nakamura initially thought it was a minor issue but helped the homeowner seek a response from WASA. When WASA would not provide a straight answer, Nakamura pressed for full test data. Nakamura later said the Post had no idea of the scope of what would follow.

The article quoted Erik Olson of the Natural Resources Defense Council, who called it a very big deal and noted that schools immediately take water out of production if levels exceed 20 ppb. WASA recommended letting taps run for 30 seconds to a minute. This article was the first public mention that the lead levels might be tied to monochloramine.

Chlorine had been stopped four years earlier due to concerns about harmful byproducts linked to cancer. Officials said chloramine might be more corrosive to lead pipes. The Army Corps of Engineers had rejected a recommendation to add phosphates to prevent lead leaching in the mid-1990s. The switch to chloramine followed EPA regulations on disinfection byproducts.

2004–05: Government hearings

At a March 2004 House Committee on Government Reform hearing, Marc Edwards testified that the switch from chlorine to chloramine caused elevated lead levels. He said chloramine leached lead not only from old lead lines but also from brass fixtures, which can contain up to eight percent lead even if classified as lead-free. Edwards warned that replacing lead lines with copper could worsen corrosion of remaining lead lines.

The chief of the Washington Aqueduct disagreed, stating tests after chloramine began showed no additional corrosiveness, and suggested adding orthophosphate as a corrosion inhibitor. In spring 2004, a temporary switch back to chlorine for annual pipe flushing caused a 25 to 30 percent drop in lead levels, supporting the chloramine theory; in one home, lead levels dropped tenfold. In 2005, President Bush proposed cutting the EPA budget by nearly half a billion dollars, mostly from clean-water programs, including an 83 percent decrease in spending on replacing aging water facilities.

2006–10: EPA, CDC, and other expert reports faulted

In January 2006, the Government Accountability Office criticized the EPA's monitoring of lead levels in drinking water, noting that data collection problems might undermine public health protection. Studies have shown no safe level for lead consumption. In their 2010 water quality report, DC Water stated that lead found in some samples was possibly due to corrosion of household plumbing or erosion of natural deposits, but did not specify locations or affected individuals.

In 2007, Environmental Health Perspectives published a paper by a team led by Tee Guidotti, who had been hired as a consultant by WASA in 2004. The paper analyzed data from the 2004 screening program and found no evidence that blood lead levels had been affected by elevated lead in drinking water, though it cautioned that a population study was not suitable for establishing such relationships and called for reducing exposure from all sources. The paper stated there appeared to be no identifiable public health impact from the elevation of lead in D.C. drinking water in 2003 and 2004.

Did You Know?

• In 1999, an EPA survey estimated that U.S. drinking-water systems needed $150 billion in repairs over the following 20 years.
• Using EPA data, the Washington Post identified 274 utilities that reported unsafe lead levels between 2000 and 2004.