What Washington DC Residents Should Know
Washington DC's drinking water comes from the Potomac River, processed through the Washington Aqueduct (operated by the Army Corps of Engineers) before distribution by DC Water. The District has a complex water quality history, most notably the lead crisis of the early 2000s when a change in disinfection chemicals caused lead to leach from service lines, resulting in dangerously high lead levels across the city.
While significant improvements have been made in the past 20 years, including enhanced treatment processes and the ongoing replacement of lead service lines, challenges remain. The city's aging infrastructure still includes thousands of lead service lines, particularly prevalent in older neighborhoods east of Rock Creek Park, Capitol Hill, and Georgetown. Partial lead line replacements (where only the public portion was replaced) can actually increase lead exposure in the short term.
Additionally, the Potomac River source water faces seasonal challenges with increased turbidity after heavy rainfall, agricultural runoff contributing to periodic increases in nitrates, and industrial contaminants like PFAS being detected at low levels. Disinfection byproducts like trihalomethanes (TTHMs) and haloacetic acids (HAAs) also remain a concern in parts of the distribution system.
Key Contaminants Found
These substances have been detected in Washington DC's water supply at levels that may be concerning for some residents.
Lead
Near Limit in Some AreasSource: Lead service lines, lead solder in plumbing, and older fixtures in pre-1986 buildings
Health Effects: Developmental delays in children, learning disabilities, reduced IQ, kidney problems, high blood pressure
DC Levels: Average 4.8 ppb (90th percentile), with approximately 5% of samples exceeding the EPA action level, particularly in homes with lead service lines or partial replacements
EPA Limit: Action level 15 ppb, but no safe level exists
Total Trihalomethanes (TTHMs)
Below Limit, But PresentSource: Byproducts formed when chlorine used to disinfect water reacts with organic matter
Health Effects: Potential increased risk of cancer with long-term exposure, liver and kidney problems
DC Levels: 38-62 ppb, varying by location and season, higher during warmer months
EPA Limit: 80 ppb
PFAS (Per- and Polyfluoroalkyl Substances)
No Federal Limit YetSource: Industrial chemicals used in non-stick cookware, waterproof fabrics, firefighting foam, and other products
Health Effects: Potential impacts on immune system, thyroid function, reproduction, and increased cancer risk
DC Levels: 4-12 ppt (parts per trillion) total PFAS detected in recent sampling
EPA Guideline: EPA has proposed 4 ppt for PFOA and PFOS
Haloacetic Acids (HAAs)
Below LimitSource: Byproducts formed when chlorine used to disinfect water reacts with organic matter
Health Effects: Potential increased risk of cancer with long-term exposure, reproductive effects
DC Levels: 15-35 ppb in most areas
EPA Limit: 60 ppb
Neighborhood Variations
Water quality can vary significantly across Washington DC's diverse neighborhoods, primarily due to differences in infrastructure age, pipe materials, and proximity to treatment facilities.
Water Quality by Area
| Neighborhood/Ward | Risk Level | Buildings Pre-1986 | Notable Concerns |
|---|---|---|---|
| Capitol Hill (Ward 6) | High | 91% | Lead, Aging Infrastructure |
| Georgetown (Ward 2) | High | 89% | Lead, Partial Replacements |
| Foggy Bottom (Ward 2) | Medium | 75% | Lead, TTHMs |
| Anacostia (Ward 8) | Medium | 68% | Lead, TTHMs, HAAs |
| Brookland/Michigan Park (Ward 5) | Medium | 72% | Lead, TTHMs |
| Petworth (Ward 4) | Medium | 76% | Lead, Partial Replacements |
| Navy Yard (Ward 6) | Low | 15% | TTHMs (Low Levels) |
| Southwest Waterfront (Ward 6) | Low | 22% | TTHMs (Low Levels) |
Data based on DC Water sampling and District housing statistics.
DC Water Quality Resources
These resources can help Washington DC residents monitor and improve their drinking water quality.
Lead Service Line Map
DC Water maintains an interactive map showing the service line materials for properties across the District. Check whether your home has lead pipes.
View MapFree Lead Testing Program
DC Water provides free lead testing kits to all District residents. This is especially important for homes in high-risk neighborhoods.
Request Testing KitLead Pipe Replacement Program
DC Water offers financial assistance programs to replace lead service lines, including free replacement for eligible low-income homeowners.
Explore ProgramWater Quality Reports
Access DC Water's annual Consumer Confidence Reports with detailed testing results and water quality data from across the District.
View ReportsWater Quality Tips for DC Residents
These simple steps can help improve your drinking water safety, especially in older neighborhoods.
Flush Your Pipes
Run cold water for 2-3 minutes before using it for drinking or cooking, especially in the morning or after periods of non-use.
Use Cold Water
Always use cold water for drinking, cooking, and preparing formula. Hot water dissolves lead and other contaminants more easily.
Use Certified Filters
Install NSF/ANSI Standard 53 certified filters for lead removal if you have lead service lines or older plumbing.
Want to know your personal water quality risk?
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