Oak Park, IL tap water
Supplied by Oak Park. Here's what its 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
Nitrate (NO₃)
Supplier's figure1.4–1.6 ppm (Low)
Typical 1.6 ppm
Low, so water changes lower your tank's nitrate well.
From the utility that supplies yours: Chicago, which supplies Oak Park (2025).
Water chemistry
General hardness
Supplier's figure130–151 ppm
Typical 140 ppm
Moderately soft to medium. Suits most community fish and plants.
From the utility that supplies yours: Chicago, which supplies Oak Park.
Carbonate hardness (alkalinity)
Supplier's figure116–126 ppm
Typical 121 ppm
Strong buffering. pH stays steady and hard to lower without RO water.
From the utility that supplies yours: Chicago, which supplies Oak Park (2017–2019).
pH
Supplier's figure8.2–9.4
Typical 8.8
Alkaline. Many utilities raise pH to protect pipes. Stability matters more than the exact number.
From the utility that supplies yours: Chicago, which supplies Oak Park (2025).
- Oak Park adds phosphate to protect pipes. It can feed algae in tanks without much plant growth.
Who supplies Oak Park, IL
Oak Park
Serves all residents · Buys water from Chicago · 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.
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Compiled by Shoal & Stem from public records. Free to cite with a link.