San Marino, CA tap water
Supplied by Cal/Am Water Company - San Marino. 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
Nitrite (NO₂)
Not detected (Low)
Not detected in testing, so any nitrite in your tank comes from the tank itself.
From EPA monitoring data (2014–2019).
Nitrate (NO₃)
15 ppm (Worth knowing)
Water changes can't take your tank's nitrate below this level.
From California Water Board lab results (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 (2023).
Water chemistry
General hardness
Supplier's figure82–291 ppm
Typical 218 ppm
Hard. Ideal for livebearers and African cichlids. Soft-water species may struggle to breed.
From the utility that supplies yours: Metropolitan Water Dist. of So. Cal. and Sierra Madre-City, Water Dept., which supplies Cal/Am Water Company - San Marino (2023–2026).
Carbonate hardness (alkalinity)
Supplier's figure68–155 ppm
Typical 128 ppm
Strong buffering. pH stays steady and hard to lower without RO water.
From the utility that supplies yours: Metropolitan Water Dist. of So. Cal. and Sierra Madre-City, Water Dept., which supplies Cal/Am Water Company - San Marino (2023–2026).
pH
8
Most community fish do well here. Stable water matters more than the exact number.
From EPA monitoring data (2014–2019).
Total dissolved solids
Supplier's figure195–666 ppm
Typical 452 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: Metropolitan Water Dist. of So. Cal. and Sierra Madre-City, Water Dept., which supplies Cal/Am Water Company - San Marino (2023–2026).
Who supplies San Marino, CA
Cal/Am Water Company - San Marino
Serves 96% of residents · Buys water from Metropolitan Water Dist. of So. Cal. · 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.