San Clemente, CA tap water
Supplied mostly by City of San Clemente, plus 1 other utility. Here's what the 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 figureUp to 14 ppm (Low)
Typically not detected
Not detected in testing, so water changes lower your tank's nitrate well.
From the utility that supplies yours: Metropolitan Water Dist. of So. Cal., which supplies City of San Clemente; Metropolitan Water Dist. of So. Cal. and Trabuco Canyon Water District and Irvine Ranch Water District, which supplies Santa Margarita Water District (2023–2026).
Copper at home taps
0.03–0.08 ppm (Low)
Typical 0.03 ppm
Low. Water that sits in household pipes overnight can carry more than this.
From California Water Board lab results; Santa Margarita Water District's 2024 water quality report (2024–2025).
Water chemistry
General hardness
Supplier's figure82–313 ppm
Typical 234 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., which supplies City of San Clemente; Santa Margarita Water District's 2024 water quality report (2023–2026).
Carbonate hardness (alkalinity)
Supplier's figure68–144 ppm
Typical 106 ppm
Moderate buffering. pH should stay fairly steady.
From the utility that supplies yours: Metropolitan Water Dist. of So. Cal., which supplies City of San Clemente; Santa Margarita Water District's 2024 water quality report (2023–2026).
pH
7–8.6
Typical 7.3
Most community fish do well here. Stable water matters more than the exact number.
From EPA monitoring data; Santa Margarita Water District's 2024 water quality report (2015–2024).
Total dissolved solids
Supplier's figure214–712 ppm
Typical 535 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., which supplies City of San Clemente; Santa Margarita Water District's 2024 water quality report (2023–2026).
Who supplies San Clemente, CA
City of San Clemente
Serves 74% of residents · Buys water from Metropolitan Water Dist. of So. Cal. · Chloramine
- 2024 water quality report
Santa Margarita Water District
Serves 18% 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.