Aptos Hills-Larkin Valley, CA tap water
Supplied mostly by City of Watsonville, 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
Nitrate (NO₃)
4.9–25 ppm (Worth knowing)
Typical 18 ppm
Water changes can't take your tank's nitrate below this level.
From California Water Board lab results; California Water Board lab results, measured before treatment (2023–2026).
Copper at home taps
0.08–0.22 ppm (Worth knowing)
Typical 0.15 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
73–340 ppm
Typical 220 ppm
Hard. Ideal for livebearers and African cichlids. Soft-water species may struggle to breed.
From California Water Board lab results, measured before treatment (2023–2026).
Carbonate hardness (alkalinity)
77–260 ppm
Typical 175 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
7.2–8.2
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 (2023–2026).
Total dissolved solids
132–460 ppm
Typical 335 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 Aptos Hills-Larkin Valley, CA
City of Watsonville
Serves 32% of residents · Lake or river water · Chlorine
Central Water District
Serves 31% of residents · Groundwater (wells) · Chlorine
Aptos Hills Mutual Water Co
Serves 6% of residents · Groundwater (wells) · Disinfectant not listed
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.