Well Water in Keene, New Hampshire

Cheshire County · Population ~23,000 (Keene); Cheshire County ~76,000 · Aquifer: Glacial Till / Bedrock / Connecticut River Valley

Hardness: Moderate to Very Hard

Arsenic: Southwest NH Hotspot

The bedrock in Cheshire County includes formations with among the highest arsenic probability in New Hampshire. The NH Geological Survey's arsenic probability maps show much of southwestern NH in the elevated risk zone.

The arsenic comes from the same granitic and metamorphic bedrock found across the state, but certain formations in the Keene area are particularly prone to releasing arsenic into groundwater. Some wells in the area have tested at multiples of the EPA standard.

Every well in Cheshire County should be tested for arsenic. See our arsenic guide.

Hardness and Minerals

Cheshire County water tends to be moderate to very hard, depending on the specific bedrock. The Connecticut River valley fills and glacial deposits can produce particularly hard water with elevated iron and manganese.

Hard water isn't a direct health threat, but it damages plumbing, appliances, and makes soap less effective. Most homeowners with very hard water benefit from a water softener.

Rural Well Challenges

Many of the smaller towns surrounding Keene — Dublin, Jaffrey, Marlborough, Swanzey — have no municipal water. Every home is on a well. This means:

• No one is testing your water for you
• No treatment infrastructure beyond what you install
• Your water quality is entirely determined by the bedrock beneath your property

The good news: NH offers treatment system rebates that can cover most or all of the cost of addressing any contaminant found in your well.

What to Test For

Cheshire County well owners should test for: arsenic, radon, uranium, bacteria, nitrates, manganese, iron, hardness, pH, and TDS.

See our testing guide for certified labs and costs.