New Hampshire’s public tap water is regulated, tested, and generally safe to drink. Community water systems must meet federal Safe Drinking Water Act standards and state-specific limits that are, in some cases, stricter than federal rules. The bigger concern in New Hampshire is private well water, which is unregulated and unmonitored, and the state’s geology introduces natural contaminants like arsenic, uranium, and radon that affect wells drilled into bedrock.
Public Water Systems vs. Private Wells
This distinction matters more in New Hampshire than in many other states. Public water systems serving cities and towns like Manchester, Nashua, and Concord are required to test regularly for dozens of contaminants and report results annually in consumer confidence reports. If something exceeds a legal limit, the utility must notify customers and take corrective action. These systems are a known quantity.
Private wells are a different story. New Hampshire has a high rate of private well use, and the state does not regulate or monitor residential well water. That responsibility falls entirely on the homeowner. The New Hampshire Department of Environmental Services (NHDES) recommends testing private wells for bacteria and nitrate every year, with a broader panel of contaminants, including arsenic, lead, copper, uranium, radon, fluoride, and manganese, tested at least once and repeated periodically. If you’re on a private well, you are your own water utility.
Arsenic in Groundwater
Arsenic is one of New Hampshire’s most widespread drinking water concerns, and it’s entirely natural. The state’s bedrock contains arsenic-bearing minerals, and when wells are drilled into fractured rock, the mineral dissolves into the water. According to the EPA, roughly one in five wells drilled into New Hampshire bedrock contain arsenic above 10 parts per billion, which is the current federal maximum contaminant level.
That 10 ppb standard only took effect in 2006. Before that, the federal limit was 50 ppb, a level set in 1975 before the health effects of lower-level exposure were understood. Long-term exposure to arsenic in drinking water is linked to increased cancer risk, cardiovascular problems, and developmental effects in children. Public water systems must treat water to stay below 10 ppb, but private well owners need to test and, if levels are elevated, install point-of-use treatment like reverse osmosis filters.
PFAS: New Hampshire’s Stricter Standards
New Hampshire set its own maximum contaminant levels for four PFAS compounds in July 2020, and they are significantly stricter than the standards many other states use. The limits are 12 parts per trillion for PFOA, 15 ppt for PFOS, 18 ppt for PFHxS, and 11 ppt for PFNA. Since October 2019, all community and non-transient public water systems have been required to test for these four compounds.
PFAS are synthetic chemicals used in nonstick coatings, firefighting foam, and industrial processes. They don’t break down easily in the environment and can accumulate in the body over time. In southern New Hampshire, PFAS contamination from a Saint-Gobain Performance Plastics facility has affected a wide area spanning parts of Merrimack, Bedford, Litchfield, Londonderry, Manchester, and Hudson. Sampling of approximately 2,600 properties identified nearly 1,200 with PFAS levels exceeding state water quality standards.
Remediation in that area is ongoing. As of March 2025, filtration systems had been installed at 690 properties, with roughly 200 additional properties designated for municipal water connections and about 350 more being evaluated for water main extensions. Saint-Gobain completed manufacturing at the facility and removed equipment in 2024, but the company continues working with NHDES on environmental cleanup, including bottled water and permanent alternate water for affected properties. New municipal water lines in the Hillcrest Road area of Litchfield reached substantial completion in fall 2024, and additional extensions in Merrimack and Bedford are expected to finish in 2025.
If you live in southern New Hampshire near any of these communities, you can check the NHDES PFAS Sampling Map online to see whether your property falls within the consent decree boundary.
Radon and Uranium
New Hampshire’s granite bedrock also releases radon and uranium into groundwater. Most people associate radon with indoor air, but it dissolves readily into well water and gets released into your home’s air when you shower, run the dishwasher, or use any faucet. The state’s action level for uranium in drinking water is 30 micrograms per liter.
For radon in water at or below 10,000 picoCuries per liter, whole-house granular activated carbon filters can be effective, though they need to be replaced every one to two years to prevent radioactive buildup in the filter media. Higher concentrations typically require aeration systems that vent radon gas outdoors before the water enters your plumbing. These contaminants primarily affect private wells. Public systems drawing from surface water reservoirs generally have minimal radon concerns.
Lead in Older Plumbing
Lead in tap water comes from pipes and service lines, not from the water source itself. Under the federal Lead and Copper Rule, the action level is 15 parts per billion for lead. New Hampshire water systems were required to submit initial service line inventories by October 2024, identifying any lead or galvanized-requiring-replacement lines in their distribution networks. Systems with lead service lines must replace them at a rate of 10 percent per year.
Even if your utility has no lead service lines in the street, lead solder in household plumbing installed before 1986 can leach into water, especially if water sits in pipes overnight. Running cold water for 30 seconds to two minutes before drinking or cooking helps flush standing water. Hot water dissolves lead more readily, so always use cold water for cooking and preparing baby formula.
How to Check Your Water Quality
If you’re on a public water system, your utility publishes an annual water quality report, sometimes called a consumer confidence report. Manchester Water Works, for example, posts theirs each April covering the previous calendar year. These reports list every contaminant tested, the levels detected, and how they compare to legal limits. You can usually find your utility’s report on their website or request a copy.
If you’re on a private well, NHDES recommends a standard analysis that covers arsenic, bacteria, chloride, copper, fluoride, hardness, iron, lead, manganese, nitrate/nitrite, pH, sodium, and uranium. Bacteria and nitrate should be tested annually. The state offers a free online tool called Be Well Informed where you can enter your test results and get an interpretation of whether any contaminants exceed health limits, along with recommendations for what type of water treatment would address them. State-certified labs across New Hampshire offer water testing kits, typically for $100 to $300 depending on the panel of contaminants.
For most people on municipal water in New Hampshire, the tap water meets all federal and state safety standards. The real gaps are in private wells, where natural contaminants and, in some areas, industrial PFAS contamination make testing essential rather than optional.