Washington DC’s drinking water carries the weight of some of America’s oldest infrastructure — and a lead contamination scandal that shook public trust nationwide. If you live in the District, here’s what you need to know about what’s coming out of your tap.
The Current State of DC’s Water
DC Water, the District’s water and sewer authority, sources its drinking water from the Potomac River via the Washington Aqueduct, which is actually operated by the U.S. Army Corps of Engineers. The system serves roughly 700,000 residents in DC proper, plus portions of northern Virginia.
Today, DC Water reports that its treated water meets all federal Safe Drinking Water Act standards. But “meets standards” and “nothing to worry about” aren’t always the same thing — especially in a city where the infrastructure dates back to the Civil War era.
The utility has made significant investments since its lead crisis, including optimized corrosion control treatment and an ongoing lead service line replacement program. But tens of thousands of lead service lines remain in the ground, and emerging contaminants like PFAS are raising new questions.
The Lead Crisis That Changed Everything
Between 2001 and 2004, DC experienced one of the worst lead-in-water contamination events in modern American history. When the Washington Aqueduct switched its disinfectant from chlorine to chloramine in 2000, it inadvertently destabilized the protective coating inside lead pipes throughout the city. Lead levels in some homes spiked to more than 80 parts per billion — over five times the EPA’s action level of 15 ppb.
What made it worse was the response. The DC Water and Sewer Authority (WASA, as it was known then) was slow to alert the public. Internal documents later revealed that officials knew about elevated lead levels months before issuing public warnings. A 2004 Washington Post investigation blew the story open, and Congressional hearings followed.
The CDC initially downplayed health impacts, but a 2009 study published in Environmental Science & Technology found that blood lead levels in DC children had risen significantly during the contamination period. Researchers estimated that hundreds — possibly thousands — of children were affected. [NEEDS VERIFICATION: exact number of children with elevated blood lead levels during this period varies by study]
The crisis led to major reforms: DC Water invested in orthophosphate corrosion control, launched an aggressive pipe replacement program, and overhauled its public communication practices.
Lead Service Lines: Still in the Ground
Despite two decades of replacement work, DC still has an estimated 28,000 lead service lines connecting homes to water mains. [NEEDS VERIFICATION: current LSL count — DC Water’s inventory is periodically updated] The city’s Lead Service Line Replacement Act has accelerated removal, and DC Water offers subsidized replacement for qualifying homeowners.
Here’s the catch: partial replacements — where only the utility-owned portion of the line gets swapped — can actually make things worse temporarily by disturbing the pipe and releasing lead particles. DC Water now prioritizes full-line replacements, but homeowners are responsible for the portion on private property, which can cost several thousand dollars.
If your home was built before 1986, there’s a real chance you have a lead service line. DC Water maintains a lookup tool on its website where you can check your address.
Anacostia River: A Contamination Legacy
While the Potomac serves as DC’s drinking water source, the Anacostia River tells a different story about the District’s environmental health. For decades, the Anacostia has been one of the most polluted urban waterways in the country.
Combined sewer overflows (CSOs) have dumped billions of gallons of mixed stormwater and raw sewage into the river annually. Industrial sites along the riverbanks contributed heavy metals, PCBs, and other toxics. The Washington Navy Yard, a Superfund-adjacent site, has been linked to groundwater contamination in the surrounding area.
DC Water’s massive Clean Rivers Project — a $2.7 billion infrastructure investment — is building underground tunnels to capture CSOs before they reach the Anacostia. The first tunnel came online in 2018, and the project is expected to reduce overflows by 96% when completed. [NEEDS VERIFICATION: current completion timeline for all tunnel segments]
The Anacostia doesn’t directly supply drinking water, but its contamination affects the broader watershed, groundwater, and the communities living along its banks — predominantly lower-income neighborhoods in Wards 7 and 8.
PFAS: The Emerging Concern
Like water systems across the country, DC faces questions about per- and polyfluoroalkyl substances (PFAS) — the so-called “forever chemicals.” The Potomac River watershed includes areas with known PFAS contamination sources, including military installations and industrial facilities upstream.
The EPA’s 2024 PFAS rule set maximum contaminant levels for six PFAS compounds in drinking water. DC Water has conducted testing and reported detections of PFAS in source water, though treated water levels have generally been below the new federal limits. [NEEDS VERIFICATION: most recent PFAS testing results from DC Water]
Given the Potomac’s role as a drinking water source for millions of people across the region, PFAS monitoring will be an ongoing concern. Residents who want additional protection can install point-of-use filtration systems rated for PFAS removal.
What the Data Shows
EPA’s ECHO database shows that DC Water has maintained general compliance with Safe Drinking Water Act monitoring requirements in recent years. The system’s lead and copper rule results have improved significantly since the crisis years, with 90th percentile lead levels well below the action level in recent testing rounds.
However, DC’s water system still contends with:
- Aging infrastructure — some water mains date back to the 1800s, and main breaks are a recurring issue
- Disinfection byproducts — total trihalomethanes (TTHMs) and haloacetic acids from chloramine treatment
- Source water vulnerability — the Potomac receives agricultural runoff, upstream wastewater discharges, and stormwater from a large watershed
What DC Residents Should Do
Check your service line. Use DC Water’s online lookup tool or call them directly. If you have a lead service line, explore the replacement program.
Run your tap. If you haven’t used your water for several hours, flush the cold water tap for 2-3 minutes before using it for drinking or cooking. This clears standing water that may have been in contact with lead pipes or fixtures.
Get your water tested. DC Water offers free lead testing kits. You can also hire an independent lab for a more comprehensive analysis including PFAS and other contaminants.
Use a certified filter. NSF/ANSI 53-certified filters can reduce lead. For PFAS, look for NSF/ANSI 58 (reverse osmosis) or NSF/ANSI 53 filters specifically rated for PFAS reduction.
Check your building’s plumbing. Even if the service line is fine, older buildings may have lead solder, brass fixtures, or galvanized pipes that contribute lead to your water.
If you’re concerned about your water quality, a certified water treatment professional can test your water and advise on solutions.