Cambridge, MA tap water
Supplied by Cambridge Water Department. 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 about 0.58 ppm of ammonia here. Some utilities switch to plain chlorine for a few weeks a year.
Safety for fish and shrimp
Ammonia (with conditioner)
Estimate0.46–0.72 ppm (Worth knowing)
Typical 0.58 ppm
This is what a conditioner frees when it breaks the chloramine apart. A cycled filter clears it within a day; a big water change in a new or very small tank adds more of it at once. Some conditioners also bind ammonia for a day or so.
Estimated from the chloramine level Cambridge Water Department reports (2025).
Nitrite (NO₂)
0.72 ppm (High)
Some nitrite shows up in this tap water, which can happen in chloramine systems, and it goes into the tank with each water change.
Published by your utility: Cambridge Water Department's 2025 water quality report.
Nitrate (NO₃)
1.1–1.9 ppm (Low)
Typical 1.5 ppm
Low, so water changes lower your tank's nitrate well.
Published by your utility: Cambridge Water Department's 2025 water quality report.
Copper at home taps (first draw)
Up to 0.04 ppm (Low)
The 90th percentile of first-draw samples from homes: water that sat in household pipes for at least six hours.
Low. Water that sits in household pipes overnight can carry more than this.
Published by your utility: Cambridge Water Department's 2025 water quality report.
Chlorine or chloramine at the tap
1.9–2.9 ppm
Typical 2.4 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: Cambridge Water Department's 2025 water quality report.
Water chemistry
General hardness
50–70 ppm
Typical 60 ppm
Soft. Good for tetras, rasboras and most shrimp. Livebearers, snails and African cichlids prefer harder water.
Published by your utility: Cambridge Water Department's website.
Carbonate hardness (alkalinity)
Not published yet
We haven't found this number yet. A drop test kit gives you your exact reading.
pH
7.2
Most community fish do well here. Stable water matters more than the exact number.
From EPA monitoring data (2016).
Total dissolved solids
323 ppm
A rough measure of everything dissolved in the water. RO water reads near 0, so TDS is a quick way to compare waters.
Published by your utility: Cambridge Water Department's 2025 water quality report.
Who supplies Cambridge, MA
- 2025 water quality report
Cambridge Water Department
Serves 98% 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.