Washington, DC tap water
Supplied by D.C. Water and Sewer Authority. Here's what its water means for your fish.
Disinfectant
Chloramine
Your water is treated with chloramine. Unlike chlorine, it doesn't gas off when water sits out, and many pitcher and fridge filters aren't rated to remove it. Conditioners that list chloramine on the label break it apart, which frees about 0.78 ppm of ammonia here. Some utilities switch to plain chlorine for a few weeks a year.
Safety for fish and shrimp
Ammonia (with conditioner)
Estimate0.02–1.02 ppm (Worth knowing)
Typical 0.78 ppm
This is what a conditioner frees when it breaks the chloramine apart. A cycled filter clears it within a day; a big water change in a new or very small tank adds more of it at once. Some conditioners also bind ammonia for a day or so.
Estimated from the chloramine level D.C. Water and Sewer Authority reports (2024).
Nitrate (NO₃)
Supplier's figure5.8–6.6 ppm (Low)
Typical 6.2 ppm
Water changes can't take your tank's nitrate below this level.
From the utility that supplies yours: Washington Aqueduct Division., which supplies D.C. Water and Sewer Authority (2015–2017).
Chlorine or chloramine at the tap
0.1–4.2 ppm
Typical 3.2 ppm
At tap levels, chlorine and chloramine are toxic to fish, shrimp and the bacteria in a filter. Water conditioners are made for this range.
Published by your utility: D.C. Water and Sewer Authority's 2024 water quality report.
Water chemistry
General hardness
78–175 ppm
Typical 126 ppm
Moderately soft to medium. Suits most community fish and plants.
Published by your utility: D.C. Water and Sewer Authority's 2024 water quality report.
Carbonate hardness (alkalinity)
Supplier's figure60 ppm
Moderate buffering. pH should stay fairly steady.
From the utility that supplies yours: Washington Aqueduct Division., which supplies D.C. Water and Sewer Authority (2015).
pH
7.6–7.8
Typical 7.7
Most community fish do well here. Stable water matters more than the exact number.
From EPA monitoring data (2017–2019).
- D.C. Water and Sewer Authority adds phosphate to protect pipes. It can feed algae in tanks without much plant growth.
Who supplies Washington, DC
- 2024 water quality report
D.C. Water and Sewer Authority
Serves all residents · Buys water from Washington Aqueduct Division. · Chloramine
Our data comes from public records and is still incomplete. Many utilities don't publish every number, so we're adding more all the time. Your city's range is a starting point: testing your own tap is the only way to know exactly what's in it.
Tap water lookup covers US cities only for now. Want to know why it matters? Read our story on tap water.
Compiled by Shoal & Stem from public records. Free to cite with a link.