Water in New Hampshire.
New Hampshire has the strictest state-level PFAS limits in the country (12 ng/L for PFOA, 15 ng/L for PFOS). The Saint-Gobain plant in Merrimack drove early state PFAS regulation. Natural arsenic in private wells is widespread.
New Hampshire was first in the U.S. to set drinking-water limits for four PFAS compounds.
How New Hampshire regulates drinking water.
Among the strictest in the U.S. NH MCLs: PFOA 12 ng/L, PFOS 15 ng/L, PFHxS 18 ng/L, PFNA 11 ng/L. Universal lead service line inventory complete.
New Hampshire Department of Environmental Services — Drinking Water and Groundwater Bureau
New Hampshire's water history, in order.
The contamination events, regulatory shifts, and major settlements that define how this state thinks about drinking water today.
- 2016
Saint-Gobain Performance Plastics in Merrimack identified as PFOA source affecting hundreds of households.
- 2019
New Hampshire sets first-in-U.S. MCLs for four PFAS compounds.
- 2023
Statewide PFAS-treatment grant program expanded.
The actual water you drink.
The physical rivers, aquifers, lakes, and reservoirs that feed New Hampshire's public water systems. Source quality is the foundation of tap quality — and where the long-term protection fights happen.
- riverPennichuck Brook + Watershed
Nashua area.
- lakeLake Massabesic
Manchester supply.
- riverMerrimack River
Central NH.
- aquiferCrystalline Bedrock Aquifers
Statewide private well source.
Source-water mix
~50% groundwater, ~50% surface water (high private well share)
Major cities served
Manchester · Nashua · Concord · Portsmouth
Who actually serves the water.
The largest public water systems in New Hampshire by population served. Click your ZIP after to see the full live EWG report for your specific utility.
- Manchester Water WorksManchester160Kserved
- Pennichuck WaterNashua145Kserved
- Portsmouth Water DepartmentPortsmouth80Kserved
Where the contamination comes from.
Every state has a different industrial fingerprint. The industries below are the dominant historical and active contamination sources in New Hampshire's drinking water systems.
Saint-Gobain Performance Plastics (Merrimack) PFAS contamination drove the state's leading-edge PFAS regulation. Pease Air Force Base / Pease Tradeport remains a major PFAS site. Limited other heavy-industry contamination.
What state data flags most consistently.
Drawn from EPA SDWIS sampling records, EWG state summaries, and regional regulatory action over the past five years. Read the full deep dive on each.
PFAS (Forever Chemicals)
A class of ~15,000 synthetic chemicals that don't break down. Now regulated for the first time.
Arsenic
A naturally occurring carcinogen. Highest in private wells and the rural Southwest.
Lead
A neurotoxic metal that leaches from old pipes and solder. No safe level for children.
Risk isn't evenly distributed.
Merrimack-area households face the most-documented PFAS exposure. Statewide rural well users face natural arsenic.
~40% on private wells — among the highest in the country. Significant geologic arsenic.
What's coming for New Hampshire's water.
Coastal sea-level rise affects southern NH shallow wells. Spring flooding intensity increases. Higher summer temperatures stress Massabesic and Pennichuck reservoir quality.
Statewide mandate
NH RSA 485:17-b (2018) requires testing in all schools and licensed childcare. Results submitted to NH DES.
Five questions for your next Consumer Confidence Report.
Your utility is required to send you a Consumer Confidence Report annually. Most are dense and procedural. These are the questions worth following up on for New Hampshire specifically.
- 1
If I'm in Merrimack, Litchfield, or surrounding towns, has my well been included in Saint-Gobain PFAS remediation?
- 2
What is my system's measured value vs. NH's 12 ng/L PFOA MCL?
- 3
Has my private well been tested for arsenic and uranium?
Most state regulators allow public records requests for the underlying lab reports behind your CCR — your utility should be able to provide them on request.
What's changed in New Hampshire water law.
Drinking water regulation moves at the state level as much as the federal level. Below are notable recent bills and regulatory actions specific to New Hampshire.
- 2022
HB 286 — Lead Service Line Inventory requirements + PFAS expansion.
- 2019
First state in the U.S. to set drinking water MCLs for four PFAS compounds.
For PFAS: NSF/ANSI P473 or reverse osmosis. For private-well arsenic: NSF/ANSI 58 RO.
We don't recommend brands — the NSF/ANSI certification number matters more than the name on the box.
This is the state. Your address is the answer.
State-level patterns don't tell you about your specific tap. Run your ZIP for the live EWG contaminant report on your utility — or build a personalized Water File for your household.
Source-water mix, utility counts, lead-service-line estimates, and private-well shares are approximate, drawn from EPA SDWIS public data and state primacy-agency summaries. Contaminant rankings reflect EWG state-level monitoring data and regional regulatory action — they are not exhaustive. Timeline events are publicly documented. See methodology for the full sourcing. Search EPA SDWIS for New Hampshire