Rialto, CA tap water
Supplied mostly by City of Rialto, plus 2 other utilities. Here's what the water means for your fish.
Disinfectant
Chlorine
Your water is treated with chlorine. It slowly gases off from standing water, and any water conditioner removes it.
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)
Up to 35 ppm (High)
Typical 26 ppm
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
0.09–0.12 ppm (Low)
Typical 0.09 ppm
Low. Water that sits in household pipes overnight can carry more than this.
From California Water Board lab results; West Valley Water District's 2024 water quality report.
Chlorine or chloramine at the tap
0.3–2.5 ppm
Typical 1.4 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: West Valley Water District's 2024 water quality report.
Water chemistry
General hardness
27–240 ppm
Typical 185 ppm
Moderately hard. Great for livebearers, and most community fish adapt.
From California Water Board lab results; West Valley Water District's 2024 water quality report (2023–2026).
Carbonate hardness (alkalinity)
120–200 ppm
Typical 150 ppm
Strong buffering. pH stays steady and hard to lower without RO water.
From California Water Board lab results; West Valley Water District's 2024 water quality report (2023–2026).
pH
6.9–8.2
Typical 7.7
Most community fish do well here. Stable water matters more than the exact number.
From EPA monitoring data; West Valley Water District's 2024 water quality report; California Water Board lab results (2017–2026).
Total dissolved solids
Estimate190–330 ppm
Typical 239 ppm
A rough measure of everything dissolved in the water. RO water reads near 0, so TDS is a quick way to compare waters.
Estimated from City of Rialto's conductivity readings; West Valley Water District's 2024 water quality report; California Water Board lab results (2023–2026).
Who supplies Rialto, CA
City of Rialto
Serves 55% of residents · Buys water from San Bernardino Valley WD · Chlorine
- 2024 water quality report
West Valley Water District
Serves 37% of residents · Lake or river water · Chlorine
San Gabriel Valley Wc - Fontana
Serves 8% of residents · Lake or river water · Chlorine
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.