Hayward, CA tap water
Supplied by City of Hayward. 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 about 0.71 ppm of ammonia here. Some utilities switch to plain chlorine for a few weeks a year.
Safety for fish and shrimp
Ammonia (with conditioner)
Estimate0.56–0.8 ppm (Worth knowing)
Typical 0.71 ppm
This is what a conditioner frees when it breaks the chloramine apart. A cycled filter clears it within a day; a big water change in a new or very small tank adds more of it at once. Some conditioners also bind ammonia for a day or so.
Estimated from the chloramine level City of Hayward reports (2025).
Nitrate (NO₃)
1.8 ppm (Low)
Low, so water changes lower your tank's nitrate well.
Published by your utility: City of Hayward's 2025 water quality report.
Copper at home taps (first draw)
Up to 0.08 ppm (Low)
The 90th percentile of first-draw samples from homes: water that sat in household pipes for at least six hours.
Low. Water that sits in household pipes overnight can carry more than this.
Published by your utility: City of Hayward's 2025 water quality report.
Chlorine or chloramine at the tap
2.3–3.3 ppm
Typical 2.9 ppm
At tap levels, chlorine and chloramine are toxic to fish, shrimp and the bacteria in a filter. Water conditioners are made for this range.
Published by your utility: City of Hayward's 2025 water quality report.
Water chemistry
General hardness
8–112 ppm
Typical 60 ppm
Soft. Good for tetras, rasboras and most shrimp. Livebearers, snails and African cichlids prefer harder water.
Published by your utility: City of Hayward's 2025 water quality report.
Carbonate hardness (alkalinity)
8–131 ppm
Typical 61 ppm
Moderate buffering. pH should stay fairly steady.
Published by your utility: City of Hayward's 2025 water quality report.
pH
8.5–9.5
Typical 9.2
Alkaline. Many utilities raise pH to protect pipes. Stability matters more than the exact number.
Published by your utility: City of Hayward's 2025 water quality report.
Total dissolved solids
24–197 ppm
Typical 111 ppm
A rough measure of everything dissolved in the water. RO water reads near 0, so TDS is a quick way to compare waters.
Published by your utility: City of Hayward's 2025 water quality report.
Who supplies Hayward, CA
- 2025 water quality report
City of Hayward
Serves 98% of residents · Buys water from San Francisco Regional Water System · 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.