District of Columbia Water and Sewer Authority

In 2008, DC Water commissioned a study, conducted by HDR Engineering, to examine the relationship between lead in drinking water and galvanized systems. The study report was presented in October 2009 and HDR is preparing a journal publication that will go through a peer review process.

The report states that in-home plumbing, specifically galvanized pipes, may contribute lead to residential drinking water taps, and should be considered as potentially important a lead source as lead service lines themselves. Other findings include:

• Galvanized pipes in residential homes can accumulate lead released from lead service lines over decades.
• Lead can be periodically released from corroded pipe surfaces and can vary from home to home.
• Homes where the service line has been replaced still may experience periodic release of lead from the corroded pipes.
• Disturbances of the corroded pipes can exacerbate lead release (water hammer or service pipe replacement —vibration of the pipes when they are suddenly turned on or off quickly).

DC Water takes the safety of District residents and its commitment to water quality seriously.

DC Water has implemented many safeguards to ensure we are held to the most stringent of standards. We strive to further reduce lead levels and provide residents with the highest quality drinking water.

DC Water has made exceptional progress in reducing drinking water lead levels. We are far below EPA limits, in fact, we are lower than the several major U.S. cities based on current consumer confidence reporting.

More than 95% of homes in the District that have lead service lines are in compliance with the EPA lead action level. DC Water continues to study lead in drinking water, and is committed to reducing lead levels in the remaining 5% of households with lead service lines.

DC Water has continually evaluated lead data and identified a correlation between lead in drinking water and residential plumbing systems with galvanized and steel pipes.

The HDR Study Recommends

• Residents should consider replacing their plumbing if they have corroded (galvanized) plumbing and have or had a lead service line.
• If pipe replacement is not an option, commercially available filters (i.e. filtration pitchers or tap filters) are available to remove lead. Be sure to purchase a treatment device certified by an independent testing organization, such as NSF International. For more information, please visit the NSF International website at www.nsf.org/certified/dwtu. Please be advised that neither EPA nor DC Water certifies or endorses specific home drinking water treatment devices.