Parker, CO tap water
Supplied mostly by Parker WSD, plus 1 other utility. Here's what the 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
Nitrite (NO₂)
Not detected (Low)
Not detected in testing, so any nitrite in your tank comes from the tank itself.
From EPA monitoring data (2012–2019).
Nitrate (NO₃)
Up to 1.2 ppm (Low)
Typically not detected
Not detected in testing, so water changes lower your tank's nitrate well.
From EPA monitoring data (2012–2019).
Water chemistry
General hardness
Supplier's figure55–198 ppm
Typical 121 ppm
Moderately soft to medium. Suits most community fish and plants.
From the utility that supplies yours: City of Aurora and Denver Water Board, which supplies Cottonwood WSD (2025).
Carbonate hardness (alkalinity)
Supplier's figure41–119 ppm
Typical 85 ppm
Moderate buffering. pH should stay fairly steady.
From the utility that supplies yours: East Cherry Creek Valley WSD and City of Aurora and Denver Water Board, which supplies Cottonwood WSD (2017–2025).
pH
Supplier's figure8–8.3
Typical 8.1
Alkaline. Many utilities raise pH to protect pipes. Stability matters more than the exact number.
From the utility that supplies yours: City of Aurora, which supplies Cottonwood WSD (2025).
Total dissolved solids
Supplier's figure98–355 ppm
Typical 230 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 Aurora and Denver Water Board, which supplies Cottonwood WSD (2025).
- Parker WSD and Cottonwood WSD add phosphate to protect pipes. It can feed algae in tanks without much plant growth.
- Parker WSD and Cottonwood WSD soften their water at the plant, so it may be softer than the local groundwater.
Who supplies Parker, CO
Parker WSD
Serves 83% of residents · Lake or river water · Chloramine
Cottonwood WSD
Serves 11% of residents · Buys water from Wise Project · 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.