Norwalk, CA tap water
Supplied mostly by Liberty Utilities - Bellflower-Norwalk, plus 2 other utilities. 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
Nitrite (NO₂)
Not detected (Low)
Not detected in testing, so any nitrite in your tank comes from the tank itself.
From EPA monitoring data (2015–2018).
Nitrate (NO₃)
Supplier's figureUp to 31 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 Liberty Utilities - Bellflower-Norwalk; EPA monitoring data; Metropolitan Water Dist. of So. Cal. and Cerritos - City, Water Dept., which supplies Norwalk - City, Water Dept. (2012–2026).
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 (2025).
Water chemistry
General hardness
Supplier's figure82–291 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 Liberty Utilities - Bellflower-Norwalk; Metropolitan Water Dist. of So. Cal., which supplies Gswc - Norwalk; Metropolitan Water Dist. of So. Cal. and Cerritos - City, Water Dept., which supplies Norwalk - City, Water Dept. (2023–2026).
Carbonate hardness (alkalinity)
Supplier's figure68–190 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 Liberty Utilities - Bellflower-Norwalk; Metropolitan Water Dist. of So. Cal., which supplies Gswc - Norwalk; Metropolitan Water Dist. of So. Cal. and Cerritos - City, Water Dept., which supplies Norwalk - City, Water Dept. (2023–2026).
pH
Supplier's figure7.7–8.7
Typical 8.2
Alkaline. Many utilities raise pH to protect pipes. Stability matters more than the exact number.
From the utility that supplies yours: Metropolitan Water Dist. of So. Cal., which supplies Liberty Utilities - Bellflower-Norwalk; EPA monitoring data; Metropolitan Water Dist. of So. Cal. and Cerritos - City, Water Dept. and Santa Fe Springs - City, Water Dept., which supplies Norwalk - City, Water Dept. (2015–2026).
Total dissolved solids
Supplier's figure214–666 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 Liberty Utilities - Bellflower-Norwalk; Metropolitan Water Dist. of So. Cal., which supplies Gswc - Norwalk; Metropolitan Water Dist. of So. Cal. and Cerritos - City, Water Dept., which supplies Norwalk - City, Water Dept. (2023–2026).
Who supplies Norwalk, CA
Liberty Utilities - Bellflower-Norwalk
Serves 60% of residents · Buys water from Metropolitan Water Dist. of So. Cal. · Chloramine
Gswc - Norwalk
Serves 26% of residents · Buys water from Metropolitan Water Dist. of So. Cal. · Chloramine
Norwalk - City, Water Dept.
Serves 10% 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.
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.