Delaware, OH tap water
Supplied mostly by Delaware City PWS, plus 1 other utility. Here's what the 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
Nitrite (NO₂)
Not detected (Low)
Not detected in testing, so any nitrite in your tank comes from the tank itself.
From EPA monitoring data (2012–2018).
Nitrate (NO₃)
0.9–6.2 ppm (Low)
Typical 2.6 ppm
Low, so water changes lower your tank's nitrate well.
From EPA monitoring data; Del-Co Water Company, Inc.'s 2025 water quality report (2012–2025).
Copper at home taps (first draw)
0.01–0.35 ppm (Worth knowing)
The 90th percentile of first-draw samples from homes: water that sat in household pipes for at least six hours.
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.
Published by your utility: Del-Co Water Company, Inc.'s 2025 water quality report.
Chlorine or chloramine at the tap
1.3–1.6 ppm
Typical 1.5 ppm
At tap levels, chlorine and chloramine are toxic to fish, shrimp and the bacteria in a filter. Water conditioners are made for this range.
Published by your utility: Del-Co Water Company, Inc.'s 2025 water quality report.
Water chemistry
General hardness
120–140 ppm
Typical 128 ppm
Moderately soft to medium. Suits most community fish and plants.
Published by your utility: Del-Co Water Company, Inc.'s website.
Carbonate hardness (alkalinity)
140–430 ppm
Typical 380 ppm
Strong buffering. pH stays steady and hard to lower without RO water.
From EPA monitoring data, measured before treatment (2014).
pH
7–8.3
Typical 7.8
Most community fish do well here. Stable water matters more than the exact number.
From EPA monitoring data, measured before treatment (2012–2014).
- Delaware City PWS and Del-Co Water Company, Inc. add phosphate to protect pipes. It can feed algae in tanks without much plant growth.
Who supplies Delaware, OH
Delaware City PWS
Serves 77% of residents · Lake or river water · Chlorine
- 2025 water quality report
Del-Co Water Company, Inc.
Serves 13% of residents · Lake or river water · 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.
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.