Grafton County, New Hampshire: drinking water report. Grafton County in central New Hampshire has a population of about 92,000, including Lebanon, Hanover…
Grafton County in central New Hampshire has a population of about 92,000, including Lebanon, Hanover (home to Dartmouth College), and several small mountain communities. Water sources range from surface impoundments to deep bedrock wells. The county's geology – fractured granite and metamorphic rock – creates groundwater systems where water moves through cracks rather than through porous material, making contamination pathways difficult to predict.
New Hampshire has been at the forefront of PFAS regulation, adopting some of the strictest standards in the country. According to the New Hampshire DES's 2024 PFAS monitoring report, the state's MCLs include 12 ppt for PFOA, 15 ppt for PFOS, and limits for four additional PFAS compounds. Several small water systems in Grafton County have detected PFAS above these thresholds, requiring treatment or alternative supply development.
Naturally occurring arsenic is common in New Hampshire's bedrock aquifers. A USGS study found that 20% of private wells in New Hampshire exceed the arsenic MCL of 10 ppb, and Grafton County's granite geology is no exception. The fractured bedrock makes well-to-well variation extreme – one property may have clean water while the neighbor's well shows elevated arsenic.
Private well testing is not optional in Grafton County – it is the only way to know what is in your water. The fractured bedrock means every well is unique, and your neighbor's results tell you nothing about yours.
Check your water for data on public systems in your area. For arsenic, only reverse osmosis and specific media filters work. For PFAS, reverse osmosis handles both. Our water filter guide covers well-water-specific systems. Pull your detailed report for any available data, and visit our New Hampshire page for statewide patterns.