Water hardness by state
How hard is the water in New Hampshire?
Tap water in New Hampshire averages 3.2 grains per gallon (55 ppm calcium carbonate). That number determines how fast limescale coats your water heater, shower glass and appliances.
Based on 182 measurements from 27 monitoring sites, 2005-04 → 2019-10.
Water hardness by county in New Hampshire
Medians of the individual measurements recorded in each county. Hardness varies far more within a state than between neighbouring states — this is where your own figure actually comes from.
| County | gpg | mg/L | Range (mg/L) | Classification |
|---|---|---|---|---|
| Rockingham County | 8.8 | 150 | 116–265 | Moderately hard water |
| Merrimack County | 1.3 | 22 | 14–42 | Soft water |
| Hillsborough County | 3.2 | 55 | 18–112 | Soft water |
| Cheshire County | 5.5 | 94 | 91–94 | Soft water |
| Carroll County | 1.2 | 20 | 16–32 | Soft water |
Range shown is the 10th-90th percentile of local measurements. Counties with fewer than five samples are omitted rather than estimated.
What 3.2 gpg means in New Hampshire
Soft water like this leaves little to no scale. Soap lathers easily, appliances stay clean and your water heater keeps its efficiency. Protection is optional — mostly useful if your utility occasionally blends in harder sources.
What it does to your home
Water heater: even a thin layer of scale insulates the heating element and drives energy use up.
Appliances: dishwashers, washing machines and coffee makers scale up and fail years early.
Fixtures and skin: white spots on faucets and glass, dry skin and dull hair after every shower.
How this figure was obtained
Median of the site-level medians at 27 groundwater monitoring sites (wells and springs — the sources most US public systems draw from) in the USGS National Water Information System (182 individual measurements, 2005-04 → 2019-10). Each site is collapsed to one value first so that a heavily sampled location cannot skew the state figure; the range shown is the 10th-90th percentile across sites. This describes the raw water resource, not a specific municipal tap after treatment.
Water Quality Portal — USGS National Water Information System (NWIS), characteristic "Hardness, Ca, Mg"Statewide average — hardness varies by utility and season. Always verify with your local water quality report.
Frequently asked questions — New Hampshire
Is 3.2 gpg considered hard water?
On the US scale, 0–3.5 gpg is soft, 3.5–7 gpg moderately hard, 7–10.5 gpg hard and above 10.5 gpg very hard. At 3.2 gpg (55 ppm), water in New Hampshire is classified as Soft water.
Does New Hampshire have a limescale problem?
Water in New Hampshire averages 3.2 gpg — Soft water. The harder the water, the faster calcium carbonate deposits build up in water heaters, appliances and pipes. Below 3.5 gpg the risk is minimal; above 7 gpg scale becomes a running cost.
How do I find the exact water hardness at my address in New Hampshire?
Check your utility's annual water quality report (Consumer Confidence Report) or your water bill, or use our free interactive hardness map. Hardness can vary widely between neighboring utilities in New Hampshire.
Do I need a salt-based water softener at 3.2 gpg?
Not necessarily. Salt softeners add sodium to your water and need constant refills. LIMPEO treats limescale with an electromagnetic field — no salt, no chemicals, no maintenance — and keeps healthy minerals in your drinking water.