El Monte, CA tap water
Supplied mostly by San Gabriel Valley Water Co.-El Monte, plus 2 other utilities. 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; EPA monitoring data (2014–2025).
Nitrate (NO₃)
5.3–32 ppm (Worth knowing)
Typical 24 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
0.06–0.26 ppm (Worth knowing)
Typical 0.13 ppm
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 (2023–2024).
Water chemistry
General hardness
82–291 ppm
Typical 269 ppm
Hard. Ideal for livebearers and African cichlids. Soft-water species may struggle to breed.
From California Water Board lab results; Metropolitan Water Dist. of So. Cal. and Sierra Madre-City, Water Dept., which supplies Cal/Am Water Company - San Marino (2023–2026).
Carbonate hardness (alkalinity)
68–220 ppm
Typical 190 ppm
Strong buffering. pH stays steady and hard to lower without RO water.
From California Water Board lab results; Metropolitan Water Dist. of So. Cal. and Sierra Madre-City, Water Dept., which supplies Cal/Am Water Company - San Marino (2023–2026).
pH
7–8
Typical 7.5
Most community fish do well here. Stable water matters more than the exact number.
From California Water Board lab results; EPA monitoring data (2014–2026).
Total dissolved solids
195–666 ppm
Typical 480 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 California Water Board lab results; Metropolitan Water Dist. of So. Cal. and Sierra Madre-City, Water Dept., which supplies Cal/Am Water Company - San Marino (2023–2026).
Who supplies El Monte, CA
San Gabriel Valley Water Co.-El Monte
Serves 63% of residents · Groundwater (wells) · Chlorine
El Monte-City, Water Dept.
Serves 12% of residents · Groundwater (wells) · Chlorine
Cal/Am Water Company - San Marino
Serves 7% 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.