Guerneville, CA tap water
Supplied mostly by Sweetwater Springs CWD - Guerneville, plus 1 other utility. 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
Nitrate (NO₃)
Up to 1.8 ppm (Low)
Typically not detected
Not detected in testing, so water changes lower your tank's nitrate well.
From California Water Board lab results, measured before treatment (2023–2026).
Copper at home taps
0.32–0.41 ppm (Worth knowing)
Typical 0.41 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 (2025).
Water chemistry
General hardness
104–160 ppm
Typical 160 ppm
Moderately hard. Great for livebearers, and most community fish adapt.
From California Water Board lab results, measured before treatment (2023–2026).
Carbonate hardness (alkalinity)
112–160 ppm
Typical 160 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
6.7–6.9
Typical 6.9
Most community fish do well here. Stable water matters more than the exact number.
From California Water Board lab results, measured before treatment; EPA monitoring data (2014–2025).
Total dissolved solids
135–190 ppm
Typical 190 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 Guerneville, CA
Sweetwater Springs CWD - Guerneville
Serves all residents · Groundwater (wells) · Chlorine
Armstrong Valley-Cal Water Service (Puc)
Serves 9% 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.
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Compiled by Shoal & Stem from public records. Free to cite with a link.