Harmony Grove, CA tap water
Supplied by Rincon del Diablo MWD (Id-1). Here's what its water means for your fish.
Disinfectant
Chloramine
Your water is treated with chloramine. Unlike chlorine, it doesn't gas off when water sits out, and many pitcher and fridge filters aren't rated to remove it. Conditioners that list chloramine on the label break it apart, which frees a little ammonia. Some utilities switch to plain chlorine for a few weeks a year.
Safety for fish and shrimp
Nitrate (NO₃)
Supplier's figure1 ppm (Low)
Low, so water changes lower your tank's nitrate well.
From the utility that supplies yours: San Diego County Water Authority, which supplies Rincon del Diablo MWD (Id-1) (2023–2026).
Copper at home taps
0.15 ppm (Worth knowing)
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
Supplier's figure209 ppm
Moderately hard. Great for livebearers, and most community fish adapt.
From the utility that supplies yours: San Diego County Water Authority, which supplies Rincon del Diablo MWD (Id-1) (2025–2026).
Carbonate hardness (alkalinity)
Supplier's figure119 ppm
Strong buffering. pH stays steady and hard to lower without RO water.
From the utility that supplies yours: San Diego County Water Authority, which supplies Rincon del Diablo MWD (Id-1) (2024–2026).
pH
Supplier's figure7.9
Most community fish do well here. Stable water matters more than the exact number.
From the utility that supplies yours: San Diego County Water Authority, which supplies Rincon del Diablo MWD (Id-1) (2025–2026).
Total dissolved solids
Supplier's figure520 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 the utility that supplies yours: San Diego County Water Authority, which supplies Rincon del Diablo MWD (Id-1) (2023–2026).
Who supplies Harmony Grove, CA
Rincon del Diablo MWD (Id-1)
Serves 77% of residents · Buys water from San Diego County Water Authority · Chloramine
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.