Oroville, CA tap water
Supplied mostly by Cal-Water Service Co.-Oroville, plus 2 other utilities. Here's what the 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 (2024–2026).
Nitrate (NO₃)
Not detected (Low)
Not detected in testing, so water changes lower your tank's nitrate well.
From California Water Board lab results (2023–2026).
Copper at home taps
0.01–0.24 ppm (Worth knowing)
Typical 0.1 ppm
Shrimp and snails are sensitive to copper. Water that sits in household pipes picks up the most; it drops once the tap has run for a minute.
From California Water Board lab results (2023–2025).
Water chemistry
General hardness
35–36 ppm
Typical 35 ppm
Soft. Good for tetras, rasboras and most shrimp. Livebearers, snails and African cichlids prefer harder water.
From California Water Board lab results (2023–2024).
Carbonate hardness (alkalinity)
40–43 ppm
Typical 43 ppm
Moderate buffering. pH should stay fairly steady.
From California Water Board lab results (2023–2025).
pH
7.2–7.6
Typical 7.2
Most community fish do well here. Stable water matters more than the exact number.
From California Water Board lab results; EPA monitoring data (2015–2026).
Total dissolved solids
28–80 ppm
Typical 76 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; South Feather W&p - Miners Ranch's conductivity readings (2023–2025).
Who supplies Oroville, CA
Cal-Water Service Co.-Oroville
Serves 48% of residents · Lake or river water · Chlorine
South Feather W&p - Miners Ranch
Serves 28% of residents · Lake or river water · Chlorine
Thermalito Water & Sewer Dist
Serves 25% 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.
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Compiled by Shoal & Stem from public records. Free to cite with a link.