Claremont, CA tap water
Supplied mostly by Gswc - Claremont, plus 2 other utilities. Here's what the water means for your fish.
Disinfectant
Chlorine or chloramine
Utilities here use chlorine or chloramine, depending on which one serves your address. Chlorine slowly gases off from standing water; chloramine doesn't.
Safety for fish and shrimp
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 (2023–2026).
Nitrate (NO₃)
1.8–29 ppm (Worth knowing)
Typical 20 ppm
Water changes can't take your tank's nitrate below this level.
From California Water Board lab results; California Water Board lab results, measured before treatment (2023–2026).
Copper at home taps
Up to 0.07 ppm (Low)
Typical 0.07 ppm
Low. Water that sits in household pipes overnight can carry more than this.
From California Water Board lab results (2023–2026).
Water chemistry
General hardness
Supplier's figure99–355 ppm
Typical 99 ppm
Moderately soft to medium. Suits most community fish and plants.
From the utility that supplies yours: Three Valleys MWD, which supplies Gswc - Claremont; California Water Board lab results; California Water Board lab results, measured before treatment (2023–2026).
Carbonate hardness (alkalinity)
Supplier's figure72–290 ppm
Typical 72 ppm
Moderate buffering. pH should stay fairly steady.
From the utility that supplies yours: Three Valleys MWD, which supplies Gswc - Claremont; California Water Board lab results; California Water Board lab results, measured before treatment (2023–2026).
pH
7.6–8.5
Typical 7.7
Most community fish do well here. Stable water matters more than the exact number.
From EPA monitoring data; California Water Board lab results; California Water Board lab results, measured before treatment (2014–2026).
Total dissolved solids
Supplier's figure250–480 ppm
Typical 250 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: Three Valleys MWD, which supplies Gswc - Claremont; California Water Board lab results; California Water Board lab results, measured before treatment (2023–2026).
Who supplies Claremont, CA
Gswc - Claremont
Serves 99% of residents · Buys water from Three Valleys MWD · Chloramine
Three Valleys MWD
Serves 36% of residents · Lake or river water · Chloramine
West End Consolidated Water Company
Serves 28% of residents · Groundwater (wells) · Chlorine
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.