Derry, NH tap water
Supplied mostly by Derry Water Dept, 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 (2014–2017).
Nitrate (NO₃)
Supplier's figureUp to 14 ppm (Low)
Typical 8.4 ppm
Water changes can't take your tank's nitrate below this level.
From the utility that supplies yours: Manchester Water Works, which supplies Derry Water Dept; EPA monitoring data (2014–2024).
Water chemistry
General hardness
Supplier's figure16 ppm
Soft. Good for tetras, rasboras and most shrimp. Livebearers, snails and African cichlids prefer harder water.
From the utility that supplies yours: Manchester Water Works, which supplies Derry Water Dept; Manchester Water Works, which supplies Drew Woods.
Carbonate hardness (alkalinity)
Supplier's figure29–56 ppm
Typical 29 ppm
Little buffering. pH can drop quickly between water changes, especially with CO₂ or an older tank.
From the utility that supplies yours: Manchester Water Works, which supplies Derry Water Dept; EPA monitoring data (2014–2019).
pH
Supplier's figure7.5–8
Typical 7.7
Most community fish do well here. Stable water matters more than the exact number.
From the utility that supplies yours: Manchester Water Works, which supplies Derry Water Dept; EPA monitoring data (2014–2024).
Total dissolved solids
Supplier's figure85–111 ppm
Typical 98 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: Manchester Water Works, which supplies Derry Water Dept; Manchester Water Works, which supplies Drew Woods.
- Derry Water Dept and Drew Woods add phosphate to protect pipes. It can feed algae in tanks without much plant growth.
Who supplies Derry, NH
Derry Water Dept
Serves 67% of residents · Buys water from Manchester Water Works · Chloramine
Drew Woods
Serves 11% of residents · Buys water from Derry Water Dept · 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.