This isn’t an industrial contamination story. Nobody dumped arsenic into New England groundwater. The arsenic in private wells across New Hampshire, Maine, Vermont, and western Massachusetts is there because of geology that predates human settlement by millions of years. That doesn’t make it less of a concern. It just means there’s no one to blame and no remediation coming.
Why New England Has This Problem
New England’s bedrock is largely granite and metamorphic rock (schist, gneiss). These formations naturally contain arsenic-bearing minerals, particularly arsenopyrite (iron arsenic sulfide). Groundwater that flows through fractured bedrock over long periods dissolves trace amounts of these minerals. Over time, arsenic accumulates in the aquifer.
This is the same geological process that creates arsenic problems in parts of West Texas, the Southwest, and internationally, in South and Southeast Asia where millions drink naturally arsenic-contaminated groundwater. The mechanism is universal: specific rock types release arsenic to water in contact with them.
Drilled wells that penetrate deep into the crystalline bedrock are most at risk. Dug wells and wells drawing from glacial outwash (sand and gravel deposits over bedrock) tend to have lower arsenic because they’re not pulling from the fractured granite aquifer.
How Common Is It
A 2017 USGS study of New England groundwater found approximately 1 in 5 private wells in the region exceeds the EPA MCL of 10 ppb. The study examined thousands of wells across the six-state region and found that New Hampshire, Maine, and Vermont had the highest rates of arsenic exceedances.
New Hampshire stands out. Studies of NH well water have found arsenic above 10 ppb in 10-20% of tested wells, depending on the area. Rockingham County (southeastern NH) and Hillsborough County (southern NH, including Manchester) have among the highest rates. The Lakes Region of NH, central Vermont, and western Massachusetts near the Pioneer Valley also have documented elevated rates.
Predictably, this is almost entirely a rural private well issue. Municipal water systems in New England that draw from groundwater test regularly and treat as needed. The risk is concentrated in the hundreds of thousands of private wells that homeowners maintain themselves, sometimes without testing for decades.
No Taste. No Smell. No Color.
Arsenic in groundwater at concentrations from 10 ppb to 100 ppb is completely undetectable by any human sense. You can’t taste it. You can’t smell it. The water looks perfectly clear. This is what makes it genuinely dangerous in a way that contaminants with obvious sensory signals aren’t: there’s no natural warning.
The only way to know is to test.
Health Effects
The International Agency for Research on Cancer (IARC) classifies arsenic as a Group 1 carcinogen. Long-term exposure above the MCL is associated with increased risk of bladder cancer, lung cancer, and skin cancers. The EPA MCLG (maximum contaminant level goal) for arsenic is 0, meaning no safe level of exposure has been established. The MCL is set at 10 ppb based on treatment feasibility and cost, not because 10 ppb has been determined safe.
Chronic arsenic exposure can also cause peripheral neuropathy, skin changes (hyperkeratosis), and cardiovascular effects. These effects are associated with long-term exposure at elevated levels, not short-term acute exposure at low concentrations.
Children face higher relative exposure from arsenic because they drink more water per pound of body weight than adults.
Testing Resources by State
Many New England households can get subsidized arsenic testing through county or state programs. Before paying for a private lab test, check these resources:
New Hampshire: the NH Department of Environmental Services (des.nh.gov) maintains a list of certified labs and runs periodic testing programs. Some communities have gotten group testing rates through their town health officer.
Maine: Maine CDC’s Health and Environmental Testing Laboratory (HETL) tests private well samples. The Maine Rural Water Association also has resources for private well owners.
Vermont: the Vermont Department of Environmental Conservation (dec.vermont.gov) maintains a list of certified labs. Vermont has free arsenic testing available for some lower-income households.
Massachusetts: the Massachusetts Department of Environmental Protection lists certified labs. Some counties run periodic well testing programs.
A basic arsenic test from a certified lab costs $15-30. Some labs offer a basic well panel (arsenic, bacteria, nitrates, pH, hardness) for $75-125 that covers the most important New England-specific concerns in one sample.
Treatment
Reverse osmosis certified to NSF/ANSI 58 for arsenic is the most reliable point-of-use treatment. Certified systems typically remove 94-99% of arsenic. An NSF 58 under-sink RO handles arsenic, and also addresses any PFAS, nitrates, or other dissolved contaminants.
Activated alumina filtration specifically targets arsenic through adsorption. It’s used in both under-sink cartridges and whole-house configurations. Whole-house activated alumina treats water at all taps, which matters for people who cook with and use significant amounts of tap water beyond just the kitchen drinking tap. Systems need periodic regeneration or cartridge replacement.
Standard activated carbon filters do not remove arsenic. Pitcher filters (including Brita, PUR, and ZeroWater) are not certified for arsenic removal. Clearly Filtered pitcher claims arsenic reduction, but RO is the more documented solution.
The arsenic contaminant page covers the chemistry and treatment options in full detail. The how to remove arsenic from water guide covers specific filter selection.
The Practical Path Forward
If you have a drilled well in New Hampshire, Maine, Vermont, or western Massachusetts, and you haven’t tested for arsenic in the last three years, test now.
A $20 arsenic test is the starting point. If it comes back below 10 ppb, you have a baseline and can retest in a few years. If it comes back above 10 ppb, an NSF 58 under-sink RO at around $200-350 brings your drinking water arsenic below the MCL. That’s a $220-370 total investment for a confirmed problem with a documented solution.
New England arsenic isn’t rare. It’s not a fringe scenario. Roughly 1 in 5 wells in this region exceeds the federal limit. The fix is straightforward. The variable is whether you know your levels. See our well water testing guide and our under-sink RO reviews for the next steps.