EPA has released a report with the results of an extensive study evaluating factors that contributed to elevated levels of lead in drinking water for many residents served by the DC Water and Sewer Authority in the early part of the decade. EPA contracted for a study to document the cause or causes of elevated lead in D.C. drinking water in order to help other water utilities avoid similar situations.
The study found that a combination of factors, rather than a single source, contributed to the problematic release of lead in water at D.C. consumer taps. Three notable factors were likely major contributors to the elevated lead releases:
- An increase in the use of chlorine in the mid-1990’s to control microbial pathogens in the water distribution system;
- pH variations and low operating pH in the distribution system; and
- The conversion from free chlorine to chloramines for final disinfection for the purpose of reducing levels of disinfection byproducts in drinking water.
“This scientific report is another important step in EPA's action plan to reduce lead in drinking water and increase public awareness about the dangers of lead and the benefits of pollution prevention,” said Benjamin H. Grumbles, assistant administrator for water. “The study underscores the importance of maintaining pipes and monitoring changes in the water treatment process. In the coming weeks, EPA will take another key step by finalizing a national rule that strengthens Safe Drinking Water Act regulations, building on lessons learned and science gained over the last three years.”