Montclair, CA tap water
Supplied by Monte Vista WD. 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 a little ammonia. Some utilities switch to plain chlorine for a few weeks a year.
Safety for fish and shrimp
Nitrate (NO₃)
13 ppm (Worth knowing)
Water changes can't take your tank's nitrate below this level.
From California Water Board lab results (2025–2026).
Copper at home taps
Not detected (Low)
Not detected in testing. Water that sits in household pipes overnight can still pick some up.
From California Water Board lab results (2025).
Water chemistry
General hardness
180 ppm
Moderately hard. Great for livebearers, and most community fish adapt.
From California Water Board lab results (2025–2026).
Carbonate hardness (alkalinity)
Supplier's figure72–260 ppm
Typical 163 ppm
Strong buffering. pH stays steady and hard to lower without RO water.
From the utility that supplies yours: City of Upland and Water Facilities Authority-Jpa and City of Chino Hills, which supplies Monte Vista WD (2023–2026).
pH
7.9
Most community fish do well here. Stable water matters more than the exact number.
From EPA monitoring data (2012).
Total dissolved solids
Supplier's figure190–900 ppm
Typical 270 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: City of Upland and Water Facilities Authority-Jpa and City of Chino Hills, which supplies Monte Vista WD (2023–2026).
- Monte Vista WD adds phosphate to protect pipes. It can feed algae in tanks without much plant growth.
Who supplies Montclair, CA
Monte Vista WD
Serves 92% of residents · Buys water from City of Upland · 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.
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Compiled by Shoal & Stem from public records. Free to cite with a link.