Oak Park, CA tap water
Part of Oak Park is supplied by Triunfo Water & Sanitation District, plus 2 other utilities. Here's what its water means for your fish.
Disinfectant
Chloramine
Utility water here 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
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)
Supplier's figureUp to 2.2 ppm (Low)
Typically not detected
Not detected in testing, so water changes lower your tank's nitrate well.
From the utility that supplies it: Calleguas Municipal Water Dist, which supplies Triunfo Water & Sanitation District; California Water Board lab results (2023–2026).
Copper at home taps
Up to 0.1 ppm (Low)
Typically not detected
Not detected in testing. Water that sits in household pipes overnight can still pick some up.
From California Water Board lab results (2023–2026).
Water chemistry
General hardness
Supplier's figure161 ppm
Moderately hard. Great for livebearers, and most community fish adapt.
From the utility that supplies it: Calleguas Municipal Water Dist, which supplies Triunfo Water & Sanitation District; California Water Board lab results; Calleguas Municipal Water Dist, which supplies California Water Service Co - Westlake (2023–2026).
Carbonate hardness (alkalinity)
Supplier's figure120 ppm
Strong buffering. pH stays steady and hard to lower without RO water.
From the utility that supplies it: Calleguas Municipal Water Dist, which supplies Triunfo Water & Sanitation District; California Water Board lab results; Calleguas Municipal Water Dist, which supplies California Water Service Co - Westlake (2023–2026).
pH
Supplier's figure7.5–8.2
Typical 8.2
Alkaline. Many utilities raise pH to protect pipes. Stability matters more than the exact number.
From the utility that supplies it: Calleguas Municipal Water Dist, which supplies Triunfo Water & Sanitation District; California Water Board lab results (2024–2026).
Total dissolved solids
Supplier's figure420 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 it: Calleguas Municipal Water Dist, which supplies Triunfo Water & Sanitation District; California Water Board lab results; Calleguas Municipal Water Dist, which supplies California Water Service Co - Westlake (2023–2026).
Who supplies Oak Park, CA
Triunfo Water & Sanitation District
Serves 34% of residents · Buys water from Calleguas Municipal Water Dist · Chloramine
Calleguas Municipal Water Dist
Serves 34% of residents · Lake or river water · Chloramine
California Water Service Co - Westlake
Serves 11% of residents · Buys water from Calleguas Municipal Water Dist · Chloramine
We couldn't fully map which utility serves Oak Park. These numbers come from the utilities we matched, which serve about 34% of residents.
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.