Rancho Cucamonga, CA tap water
Supplied by Cucamonga Valley Water District. Here's what its water means for your fish.
Disinfectant
Chlorine
Your water is treated with chlorine. It slowly gases off from standing water, and any water conditioner removes it.
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 (2025).
Nitrate (NO₃)
2.3 ppm (Low)
Low, so water changes lower your tank's nitrate well.
From California Water Board lab results (2023–2026).
Copper at home taps
Not detected (Low)
Not detected in testing. Water that sits in household pipes overnight can still pick some up.
From California Water Board lab results (2024).
Water chemistry
General hardness
96–183 ppm
Typical 138 ppm
Moderately soft to medium. Suits most community fish and plants.
From California Water Board lab results, measured before treatment (2023–2026).
Carbonate hardness (alkalinity)
100–160 ppm
Typical 145 ppm
Strong buffering. pH stays steady and hard to lower without RO water.
From California Water Board lab results, measured before treatment (2023–2026).
pH
8.4
Alkaline. Many utilities raise pH to protect pipes. Stability matters more than the exact number.
From California Water Board lab results (2024–2025).
Total dissolved solids
150–315 ppm
Typical 200 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 California Water Board lab results, measured before treatment (2023–2026).
Who supplies Rancho Cucamonga, CA
Cucamonga Valley Water District
Serves 95% of residents · Lake or river water · 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.