For 2025–26, the big picture in New Hampshire is this: public water systems are regulated and routinely monitored, but have become less forthecoming and transparent with their findings.Private well water also remains a bigger variable and a big risk area for many homeowners. NHDES says PFAS has affected wells throughout the state, especially in southern New Hampshire, and almost half of New Hampshire residents rely on private wells, where testing and treatment are the homeowner’s responsibility. (EWG)
Natural vs and man-made contamination
The most important current concerns are still the same mix of natural contaminants and man-made contamination. On the natural side, New Hampshire is known for arsenic, radon, uranium, iron, and manganese in groundwater. USGS reports that about 55% of the state is more likely than not to have elevated radon in groundwater, and older but still foundational USGS work found elevated arsenic to be a major concern in southeastern New Hampshire bedrock wells.
Per- and polyfluoroalkyl substances (PFAS)
PFAS are a large, complex group of synthetic chemicals that have been used in consumer products around the world since about the 1950s. They are ingredients in various everyday products. For example, PFAS are used to keep food from sticking to packaging or cookware, make clothes and carpets resistant to stains, and create firefighting foam that is more effective. PFAS molecules have a chain of linked carbon and fluorine atoms. Because the carbon-fluorine bond is one of the strongest, these chemicals do not degrade easily in the environment.
On the man-made side, PFAS remains one of the headline issues in 2025–26, especially in southern New Hampshire and in known hot spot areas tied to Pease and Coakley. NHDES says PFAS has been detected in about 30% of sampled public water system sources, though actual exceedances of standards are less common than detections alone. The state is still actively running its PFAS Removal Rebate Program for Private Wells, which is a good sign that PFAS treatment remains a live issue for homeowners.
For private wells, the practical 2025–26 message is: don’t assume clear water is clean water. UNH Extension says a standard well-water analysis in New Hampshire should look at contaminants such as arsenic, copper, iron, nitrate, bacteria, fluoride, lead, pH, uranium, chloride, hardness, manganese, and sodium. NHDES continues to recommend regular testing, especially because private wells can also be affected by pollutants such as PFAS and MTBE.
What about Public/Municipal Water?
For public drinking water, the state’s 2025 compliance materials suggest the system remains active and structured, with annual reporting and enforcement for systems that fail to meet requirements. That points to a public-water landscape that is monitored and managed, even while emerging contaminants and source-water protection remain ongoing challenges.
New Hampshire water is not uniformly bad, but it is highly variable. Public systems are generally monitored and regulated. Private wells are where homeowners need to be most proactive, especially for arsenic in southeastern areas, radon/uranium in parts of the state, PFAS in southern and seacoast hot spots, and common well issues like iron, manganese, hardness, bacteria, nitrate, sodium, and chloride.
