Durham, OR tap water
Supplied mostly by City of Tigard, plus 1 other utility. Here's what the water means for your fish.
Disinfectant
Chlorine or chloramine
Utilities here use chlorine or chloramine, depending on which one serves your address. Chlorine slowly gases off from standing water; chloramine doesn't.
Safety for fish and shrimp
Nitrite (NO₂)
Up to 0.13 ppm (Low)
Typical 0.07 ppm
Essentially none, so any nitrite in your tank comes from the tank itself.
From EPA monitoring data (2012–2019).
Nitrate (NO₃)
Up to 7.6 ppm (Low)
Typical 2.4 ppm
Low, so water changes lower your tank's nitrate well.
From EPA monitoring data (2012–2019).
Water chemistry
General hardness
Supplier's figure7–80 ppm
Typical 9 ppm
Soft. Good for tetras, rasboras and most shrimp. Livebearers, snails and African cichlids prefer harder water.
From the utility that supplies yours: Portland Water Bureau, which supplies City of Tualatin (2025).
Carbonate hardness (alkalinity)
35 ppm
Little buffering. pH can drop quickly between water changes, especially with CO₂ or an older tank.
From EPA monitoring data (2015).
pH
Supplier's figure8–9
Typical 8.5
Alkaline. Many utilities raise pH to protect pipes. Stability matters more than the exact number.
From the utility that supplies yours: Portland Water Bureau, which supplies City of Tualatin (2025).
Who supplies Durham, OR
City of Tigard
Serves 81% of residents · Buys water from Lake Oswego - Tigard Water Supply · Chlorine
City of Tualatin
Serves 17% of residents · Buys water from Portland Water Bureau · 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.
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.