Carson, CA tap water
Supplied mostly by California Water Service Co. - Dominguez, 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 a little ammonia. Some utilities switch to plain chlorine for a few weeks a year.
Safety for fish and shrimp
Ammonia
0.02–1.09 ppm (Worth knowing)
Typical 0.52 ppm
Ammonia in the water as delivered. 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.
From California Water Board lab results; the chloramine level Golden State Water Company (GSWC) reports (2023–2026).
Nitrite (NO₂)
Not detected (Low)
Not detected in testing, so any nitrite in your tank comes from the tank itself.
From California Water Board lab results (2024–2026).
Nitrate (NO₃)
Up to 2.9 ppm (Low)
Typically not detected
Not detected in testing, so water changes lower your tank's nitrate well.
From California Water Board lab results; Metropolitan Water Dist. of So. Cal., which supplies Golden State Water Company (GSWC) (2023–2026).
Copper at home taps
0.02–0.12 ppm (Low)
Typical 0.02 ppm
Low. Water that sits in household pipes overnight can carry more than this.
From California Water Board lab results; Golden State Water Company (GSWC)'s 2025 water quality report (2023–2025).
Chlorine or chloramine at the tap
0.1–4.5 ppm
Typical 2.4 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: Golden State Water Company (GSWC)'s 2025 water quality report.
Water chemistry
General hardness
Estimate96–280 ppm
Typical 181 ppm
Moderately hard. Great for livebearers, and most community fish adapt.
Estimated from California Water Service Co. - Dominguez's calcium and magnesium readings; Golden State Water Company (GSWC)'s 2025 water quality report (2023–2026).
Carbonate hardness (alkalinity)
93–200 ppm
Typical 175 ppm
Strong buffering. pH stays steady and hard to lower without RO water.
From California Water Board lab results; Golden State Water Company (GSWC)'s 2025 water quality report (2023–2026).
pH
7.9–8.5
Typical 8.1
Alkaline. Many utilities raise pH to protect pipes. Stability matters more than the exact number.
From California Water Board lab results; Golden State Water Company (GSWC)'s 2025 water quality report (2023–2026).
Total dissolved solids
Supplier's figure214–666 ppm
Typical 535 ppm
A rough measure of everything dissolved in the water. RO water reads near 0, so TDS is a quick way to compare waters.
From the utility that supplies yours: Metropolitan Water Dist. of So. Cal., which supplies California Water Service Co. - Dominguez; Golden State Water Company (GSWC)'s 2025 water quality report (2023–2026).
Who supplies Carson, CA
California Water Service Co. - Dominguez
Serves 93% of residents · Buys water from Metropolitan Water Dist. of So. Cal. · Chloramine
- 2025 water quality report
Golden State Water Company (GSWC)
Serves 9% of residents · Buys water from Metropolitan Water Dist. of So. Cal. · 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.