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New Hampshire Water Quality
131
Utilities in database
0.8M
Residents served
55%
On private wells
2
Key contaminants tracked
Drinking Water in New Hampshire
New Hampshire has 131 community water systems serving approximately 0.8 million residents. Primary water sources include groundwater. The most commonly reported contaminants include disinfection byproducts, nitrates. 55% of New Hampshire residents rely on private wells. DES holds primary enforcement authority under the Safe Drinking Water Act.
Utilities in New Hampshire
76–100 of 131Hinsdale Water Dept/downtown
NH1151020 · 1,600 served
Contoocook Village Pct
NH1191010 · 1,600 served
Ashland Water Dept
NH0101010 · 1,525 served
Gunstock Acres Village Dist
NH0881020 · 1,440 served
Sanbornville Water Dept
NH2391010 · 1,425 served
Drew Woods
NH0612150 · 1,408 served
Rockingham County Complex
NH0284010 · 1,387 served
Enfield Water Dept
NH0751010 · 1,345 served
Colebrook Water Works
NH0481010 · 1,300 served
Emerald Lake
NH1141020 · 1,300 served
Waterville Estate Vlg Dist/w
NH0341030 · 1,250 served
Village District of Eidelweiss
NH1461010 · 1,200 served
Troy Water Works
NH2361010 · 1,200 served
Powder Hill
NH0192050 · 1,155 served
Grasmere Water Pct/main
NH0911020 · 1,125 served
Greenville Water Dept
NH0991010 · 1,100 served
Walpole Water Dept
NH2401010 · 1,057 served
Rosebrook Water
NH0382010 · 1,050 served
Lisbon Water Dept
NH1361010 · 1,010 served
Exeter River Mobile Home Park
NH0803020 · 980 served
Williamsburg
NH1851010 · 928 served
Antrim Sewer and Water Dept
NH0091010 · 920 served
New Castle Water Works
NH1661010 · 910 served
Cabot Preserve
NH0192070 · 878 served
Brook Park Ests
NH1392060 · 875 served
Key Contaminant Concerns in New Hampshire
Nitrates
Nitrate (NO₃⁻) is a nitrogen-containing compound that forms naturally through the decomposition of organic matter. At elevated concentrations — almost always from human activity — nitrate interferes with the blood's ability to carry oxygen. The United States produces over 23 million tons of nitrogen fertilizer annually, making agricultural runoff the dominant source of nitrate contamination.
DBPs
When utilities add chlorine to water to kill pathogens, it reacts with dissolved organic matter — leaves, algae, soil — to produce disinfection byproducts (DBPs). Over 600 DBPs have been identified. The EPA regulates two groups: total trihalomethanes (TTHMs, including chloroform) and haloacetic acids (HAA5). DBP levels tend to be highest in surface water systems and in warm months when organic matter is elevated.
New Hampshire Water FAQs
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Data source: Utility data from EPA SDWIS. 131 active community water systems ingested. CCR contaminant data ingestion in progress.
Last updated: 2026-04-22