Rohnert Park, CA tap water
Supplied mostly by City of Rohnert Park, 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 17 ppm (Low)
Typical 5.3 ppm
Water changes can't take your tank's nitrate below this level.
From California Water Board lab results, measured before treatment; Sonoma County Water Agency, which supplies Penngrove Water Company (Puc), measured before treatment (2023–2026).
Copper at home taps
0.06 ppm (Low)
Low. Water that sits in household pipes overnight can carry more than this.
From California Water Board lab results (2024–2025).
Water chemistry
General hardness
38–257 ppm
Typical 159 ppm
Moderately hard. Great for livebearers, and most community fish adapt.
From California Water Board lab results, measured before treatment; Sonoma County Water Agency, which supplies Penngrove Water Company (Puc), measured before treatment (2023–2026).
Carbonate hardness (alkalinity)
93–230 ppm
Typical 180 ppm
Strong buffering. pH stays steady and hard to lower without RO water.
From California Water Board lab results, measured before treatment; Sonoma County Water Agency, which supplies Penngrove Water Company (Puc), measured before treatment (2023–2026).
pH
7.3–8.3
Typical 7.6
Most community fish do well here. Stable water matters more than the exact number.
From California Water Board lab results, measured before treatment; Sonoma County Water Agency, which supplies Penngrove Water Company (Puc), measured before treatment (2023–2026).
Total dissolved solids
130–350 ppm
Typical 300 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; Sonoma County Water Agency, which supplies Penngrove Water Company (Puc), measured before treatment (2023–2026).
Who supplies Rohnert Park, CA
City of Rohnert Park
Serves 93% of residents · Groundwater (wells) · Chlorine
Penngrove Water Company (Puc)
Serves 6% of residents · Buys water from Sonoma County Water Agency · 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.