We read 18 results from D.C. Water and Sewer Authority’s 2024 water quality report. No results over a legal limit; 5 above a health goal or guideline.
Serves about 632,323 people · Water system ID DC0000002 · Read the district’s 2024 report (opens in a new tab)
Open this district in the water lookupCompare with your own test results, see the district map and get matched filters.
Results from the 2024 report
Each number is copied from the district’s report and links to the page it’s printed on. Where the report lists several plants, wells or purchased water, the highest is shown.
| Contaminant | Result | Health goal | Legal limit | What it means |
|---|---|---|---|---|
| Arsenichighest measured · range 0.4 to 0.4 · Water entering DC Water's system · 2024 report, page 19 | 0.4 ppb | 0.004 ppb | 10 ppb | Above the health goal100x the health goal |
| Atrazinehighest measured · range ND to 0.2 · Water entering DC Water's system · 2024 report, page 20 | 0.2 ppb | 0.15 ppb | 3 ppb | Above the health goal1.3x the health goal |
| Lead90th percentile of 105 homes tested, 1 over the action level · Customer taps, Jul-Dec (105 samples), highest of 2 sources · 2024 report, page 21 | 2 ppb | 0.2 ppb | 15 ppb (action level) | Above the health goal10x the health goal |
| PFOA (a PFAS)average · range ND to 2 · Voluntary monitoring · 2024 report, page 22 | 0.3 ppt | 0.007 ppt | 4 ppt from 2029 | Above the health goal43x the health goal |
| PFOS (a PFAS)average · range ND to 2.4 · Voluntary monitoring · 2024 report, page 22 | 1.7 ppt | 1 ppt | 4 ppt from 2029 | Above the health goal1.7x the health goal |
| Bariumhighest measured · range 0.04 to 0.04 · Water entering DC Water's system · 2024 report, page 19 | 0.04 ppm | 2 ppm | 2 ppm | Below the health goal |
| Chloraminehighest running annual average · range 0.1 to 4.2 · Distribution system · 2024 report, page 20 | 3.2 ppm | None set | 4 ppm | Below the legal limit |
| Copper90th percentile of 105 homes tested, 0 over the action level · Customer taps, Jan-Jun (105 samples), highest of 2 sources · 2024 report, page 21 | 0.1 ppm | 0.3 ppm | 1.3 ppm (action level) | Below the health goal |
| Cyanidehighest measured · range 8 to 8 · printed as 0.008 ppm · Water entering DC Water's system · 2024 report, page 19 | 8 ppb | 150 ppb | 200 ppb | Below the health goal |
| Disinfection byproducts (HAA5)highest running annual average · range 13 to 55 · Distribution system · 2024 report, page 20 | 35 ppb | None set | 60 ppb | Below the legal limit |
| Disinfection byproducts (TTHM)highest running annual average · range 22 to 68 · Distribution system · 2024 report, page 20 | 55 ppb | None set | 80 ppb | Below the legal limit |
| Fluoridehighest measured · range 0.7 to 0.8 · Water entering DC Water's system · 2024 report, page 19 | 0.8 ppm | 1 ppm | 4 ppm | Below the health goal |
| Nitrate (as N)highest measured · range 0.3 to 2 · Water entering DC Water's system · 2024 report, page 19 | 2 ppm | 10 ppm | 10 ppm | Below the health goal |
| Turbidity (cloudiness)highest measured · Washington Aqueduct plants · 2024 report, page 19 | 0.66 NTU | None set | 1 NTU | Below the legal limit |
| Hardnessaverage · range 4.56 to 10.2 · Water entering DC Water's system · 2024 report, page 21 | 7.37 gpg (126 ppm) | — | — | Hard |
| Nickelaverage · range 0.7 to 1 · Water entering DC Water's system · 2024 report, page 21 | 0.8 ppb | None set | None | No health limit |
| PFBS (a PFAS)average · range ND to 2.6 · Voluntary monitoring · 2024 report, page 22 | 0.6 ppt | None set | None | No health limit |
| Sodiumaverage · range 16 to 25 · Water entering DC Water's system · 2024 report, page 21 | 19 ppm | None set | None | No health limit |
Utility results describe the whole system, measured where water enters the pipes, not your tap. Your home’s plumbing can add lead or copper.
What you can do
Nothing here is an emergency notice: if the district has a violation, it must tell customers directly. If you’d like to lower these at your tap, these are the treatments that remove them, and the catalog shows the models certified for each. Ranking is by certified removal; commissions never change the order.
Industrial chemicals and pesticides
Found: Atrazine
What removes it: Carbon block or RO.
Lead
Found: Lead
What removes it: Certified carbon block or RO.
PFAS ("forever chemicals")
Found: PFOA (a PFAS), PFOS (a PFAS)
What removes it: Reverse osmosis.
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