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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
126–131 of 131Key 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.
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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