South Pasadena, CA tap water
Supplied by City of South Pasadena. 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 California Water Board lab results (2023–2025).
Nitrate (NO₃)
21 ppm (Worth knowing)
High for tap water. Water changes can't take your tank's nitrate below this level.
From California Water Board lab results (2023–2026).
Copper at home taps
0.15 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 (2024).
Water chemistry
General hardness
Supplier's figure82–303 ppm
Typical 235 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 Pasadena Water and Power, which supplies City of South Pasadena (2023–2026).
Carbonate hardness (alkalinity)
Supplier's figure68–210 ppm
Typical 112 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 Pasadena Water and Power, which supplies City of South Pasadena (2023–2026).
pH
Supplier's figure7.1–8.7
Typical 7.8
Most community fish do well here. Stable water matters more than the exact number.
From the utility that supplies yours: Metropolitan Water Dist. of So. Cal. and Pasadena Water and Power, which supplies City of South Pasadena (2023–2026).
Total dissolved solids
Supplier's figure214–690 ppm
Typical 472 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 Pasadena Water and Power, which supplies City of South Pasadena (2023–2026).
Who supplies South Pasadena, CA
City of South Pasadena
Serves all 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.
Tap water lookup covers US cities only for now. Want to know why it matters? Read our story on tap water.
Compiled by Shoal & Stem from public records. Free to cite with a link.