Concord, New Hampshire — the state capital with about 44,000 residents — draws its drinking water primarily from Penacook Lake (also known as Turkey Pond), a 255-acre reservoir about five miles northwest of the city center. The source water is clean. The challenges are in the geology beneath Concord’s feet and the industrial contamination spreading across southern New Hampshire.
PFAS: New Hampshire’s Statewide Crisis
New Hampshire has adopted some of the most protective PFAS standards in the country — MCLs of 12 ppt for PFOA, 15 ppt for PFOS, 18 ppt for PFHxS, and 11 ppt for PFNA. These standards are far stricter than the EPA’s current federal levels.
The state set these standards for good reason. Southern New Hampshire has multiple significant PFAS contamination sources:
- Saint-Gobain Performance Plastics — The Merrimack facility’s air emissions contaminated groundwater across a wide area of southern NH
- Pease International Tradeport — The former Pease Air Force Base in Portsmouth has one of the most well-documented PFAS contamination plumes in the country
- Coakley Landfill in North Hampton — PFAS contamination from this Superfund site has affected surrounding wells
- Multiple municipal wells statewide have tested positive for PFAS, some requiring treatment or shutdown
Concord’s position in central New Hampshire places it between the major PFAS sources in the southern part of the state. Concord Water has tested for PFAS and reports compliance with New Hampshire’s strict standards. The city’s surface water source (Penacook Lake) and supplemental groundwater wells have shown low-level PFAS detections consistent with atmospheric deposition.
Granite State Geology: Natural Contaminants
New Hampshire’s nickname — the Granite State — hints at a water quality challenge unique to New England. The state’s bedrock geology produces naturally occurring contaminants in groundwater:
- Arsenic — New Hampshire has some of the highest naturally occurring arsenic levels in the country. Approximately 20-30% of private wells in the state have arsenic above the EPA MCL of 10 µg/L. The arsenic dissolves from bedrock formations and enters groundwater naturally.
- Radon — Granite bedrock produces radon gas, which dissolves into groundwater. New Hampshire has some of the highest waterborne radon levels in the nation. While there’s no federal MCL for radon in water, the EPA has proposed an alternative MCL of 4,000 pCi/L and a simultaneous multimedia mitigation approach of 300 pCi/L.
- Uranium — Found in some granite formations, uranium can be elevated in private wells drilled into bedrock
These natural contaminants are primarily a concern for the estimated 40% of New Hampshire residents who rely on private wells. Municipal systems like Concord’s treat or blend to manage these contaminants.
Penacook Lake: A Well-Protected Source
Concord’s Penacook Lake is surrounded by city-owned watershed land, and access is restricted. The lake receives minimal treatment — primarily chlorination for disinfection — reflecting its high baseline quality. The water system also uses:
- Supplemental groundwater wells
- A secondary surface water source from the Contoocook River (emergency use)
This simplicity is a strength when the source water is clean, but it means less redundancy if contamination enters the watershed.
What the Data Shows
From Concord’s most recent Consumer Confidence Report:
- All regulated contaminants within EPA and NH state limits
- PFAS below NH’s strict MCLs
- Arsenic in groundwater wells managed through blending and treatment
- Trihalomethanes and haloacetic acids from chlorination — within limits
- Lead at 90th percentile below action level
- No SDWA violations
What Concord Residents Should Do
- Private well owners — Test for arsenic, radon, uranium, PFAS, and bacteria. This isn’t optional in New Hampshire — the geology makes testing essential.
- Know NH’s strict PFAS standards — NH’s MCLs are significantly lower than federal limits. Concord Water meets these standards, but continued monitoring matters.
- Radon in water — If you’re on a private well and have elevated radon in your indoor air, test your water too. Aeration systems effectively remove waterborne radon.
- Arsenic treatment — If your well has arsenic above 10 µg/L, reverse osmosis at the point of use or whole-house treatment is effective. Don’t ignore it — chronic arsenic exposure is a serious health risk.
- Penacook Lake watershed — Support watershed protection efforts. Concord’s relatively simple treatment works because the source water is clean.
New Hampshire’s water quality story is a lesson in both natural and man-made contamination. Concord benefits from careful source water protection, but the state’s geology and industrial contamination mean vigilance is non-negotiable — especially for private well owners.
If you’re concerned about your water quality, a certified water treatment professional can test your water and advise on appropriate treatment solutions.