Riverside, CA tap water
Supplied mostly by Riverside Public Utilities (RPU), plus 1 other utility. Here's what the water means for your fish.
Disinfectant
Chlorine or chloramine
Utilities here use chlorine or chloramine, depending on which one serves your address. Chlorine slowly gases off from standing water; chloramine doesn't.
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 (2023–2026).
Nitrate (NO₃)
1.2–29 ppm (Worth knowing)
Typical 24 ppm
High for tap water. Water changes can't take your tank's nitrate below this level.
From Riverside Public Utilities (RPU)'s 2025 water quality report; California Water Board lab results (2025–2026).
Copper at home taps (first draw)
0.02–0.8 ppm (Worth knowing)
The 90th percentile of first-draw samples from homes: water that sat in household pipes for at least six hours.
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 Riverside Public Utilities (RPU)'s 2025 water quality report; California Water Board lab results.
Chlorine or chloramine at the tap
0.1–0.8 ppm
Typical 0.6 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: Riverside Public Utilities (RPU)'s 2025 water quality report.
Water chemistry
General hardness
8–570 ppm
Typical 197 ppm
Moderately hard. Great for livebearers, and most community fish adapt.
From Riverside Public Utilities (RPU)'s 2025 water quality report; Metropolitan Water Dist. of So. Cal. and City of Riverside and Eastern Municipal WD and Western MWD and Chino Basin Desalter Auth. - Desalter 2, which supplies Western MWD (2023–2026).
Carbonate hardness (alkalinity)
9–360 ppm
Typical 157 ppm
Strong buffering. pH stays steady and hard to lower without RO water.
From Riverside Public Utilities (RPU)'s 2025 water quality report; Metropolitan Water Dist. of So. Cal. and City of Riverside and Eastern Municipal WD and Western MWD and Chino Basin Desalter Auth. - Desalter 2, which supplies Western MWD (2023–2026).
pH
7.4–8.5
Typical 8
Most community fish do well here. Stable water matters more than the exact number.
From Riverside Public Utilities (RPU)'s 2025 water quality report; California Water Board lab results (2025–2026).
Total dissolved solids
27–1150 ppm
Typical 357 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 Riverside Public Utilities (RPU)'s 2025 water quality report; Metropolitan Water Dist. of So. Cal. and City of Riverside and Eastern Municipal WD and Western MWD and Chino Basin Desalter Auth. - Desalter 2, which supplies Western MWD (2023–2026).
- Western MWD adds phosphate to protect pipes. It can feed algae in tanks without much plant growth.
Who supplies Riverside, CA
- 2025 water quality report
Riverside Public Utilities (RPU)
Serves 88% of residents · Groundwater fed by surface water · Chlorine
Western MWD
Serves 11% 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.