Great Falls, MT tap water
Supplied by City of Great Falls. Here's what its 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 (2017–2019).
Nitrate (NO₃)
Not published yet
We haven't found this number yet. A drop test kit gives you your exact reading.
Water chemistry
General hardness
Not published yet
We haven't found this number yet. A drop test kit gives you your exact reading.
Carbonate hardness (alkalinity)
116–119 ppm
Typical 118 ppm
Strong buffering. pH stays steady and hard to lower without RO water.
From EPA monitoring data (2012–2019).
pH
7.4–7.6
Typical 7.5
Most community fish do well here. Stable water matters more than the exact number.
From EPA monitoring data (2012–2019).
Who supplies Great Falls, MT
City of Great Falls
Serves 99% of residents · Lake or river water · 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.