Twain Harte, CA tap water
Supplied mostly by Twain Harte Community Services District, 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 (2023–2025).
Nitrate (NO₃)
Not detected (Low)
Not detected in testing, so water changes lower your tank's nitrate well.
From California Water Board lab results (2023–2025).
Copper at home taps
0.07–0.14 ppm (Worth knowing)
Typical 0.14 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 (2023–2026).
Water chemistry
General hardness
8–27 ppm
Typical 27 ppm
Soft. Good for tetras, rasboras and most shrimp. Livebearers, snails and African cichlids prefer harder water.
From California Water Board lab results (2023–2025).
Carbonate hardness (alkalinity)
10–41 ppm
Typical 41 ppm
Moderate buffering. pH should stay fairly steady.
From California Water Board lab results; California Water Board lab results, measured before treatment (2023–2026).
pH
6.3–7.8
Typical 7.8
Most community fish do well here. Stable water matters more than the exact number.
From California Water Board lab results; EPA monitoring data (2019–2025).
Total dissolved solids
16–56 ppm
Typical 36 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 (2023–2025).
- Twain Harte Community Services District, Tud - Upper Basin Water System and Twain Harte Valley Mwc add phosphate to protect pipes. It can feed algae in tanks without much plant growth.
Who supplies Twain Harte, CA
Twain Harte Community Services District
Serves 54% of residents · Lake or river water · Chlorine
Tud - Upper Basin Water System
Serves 41% of residents · Lake or river water · Chlorine
Twain Harte Valley Mwc
Serves 5% 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.