Potomac Mills, VA tap water
Supplied mostly by Prince William Water, plus 1 other utility. Here's what the 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 0.73 ppm of ammonia here. Some utilities switch to plain chlorine for a few weeks a year.
Safety for fish and shrimp
Ammonia (with conditioner)
Estimate0.15–0.97 ppm (Worth knowing)
Typical 0.73 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 Prince William Water reports (2024).
Nitrite (NO₂)
0.01–0.53 ppm (Low)
Typical 0.01 ppm
Essentially none, so any nitrite in your tank comes from the tank itself.
Published by your utility: Prince William Water's 2024 water quality report.
Nitrate (NO₃)
Supplier's figure1–9.3 ppm (Low)
Typical 5.1 ppm
Water changes can't take your tank's nitrate below this level.
From the utility that supplies yours: Fairfax County Water Authority, which supplies Prince William Water; Fairfax County Water Authority, which supplies Dale City (2024).
Chlorine or chloramine at the tap
0.6–4 ppm
Typical 3 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: Prince William Water's 2024 water quality report.
Water chemistry
General hardness
Supplier's figure84–170 ppm
Typical 127 ppm
Moderately soft to medium. Suits most community fish and plants.
From the utility that supplies yours: Fairfax County Water Authority, which supplies Prince William Water; Fairfax County Water Authority, which supplies Dale City.
Carbonate hardness (alkalinity)
Supplier's figure54–88 ppm
Typical 77 ppm
Moderate buffering. pH should stay fairly steady.
From the utility that supplies yours: Fairfax County Water Authority, which supplies Prince William Water; EPA monitoring data (2012–2019).
pH
Supplier's figure7.3–7.6
Typical 7.3
Most community fish do well here. Stable water matters more than the exact number.
From the utility that supplies yours: Fairfax County Water Authority, which supplies Prince William Water; EPA monitoring data (2012–2019).
- Prince William Water and Dale City add phosphate to protect pipes. It can feed algae in tanks without much plant growth.
Who supplies Potomac Mills, VA
- 2024 water quality report
Prince William Water
Serves all residents · Buys water from Fairfax County Water Authority · Chloramine
Dale City
Serves 6% of residents · Buys water from Fairfax County Water Authority · 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.
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Compiled by Shoal & Stem from public records. Free to cite with a link.