Well water in Exeter, New Hampshire
In Exeter, none of 54 private wells tested between 2006 and 2020 had fluoride above the New Hampshire guidance level (4 mg/L), according to NH DHHS.
54 private wells tested 2006 to 2020 in state summaries; 65 individual samples from 65 wells, 1956 to 2023. Data refreshed September 3, 2026.
NHDES samples private wells near known or suspected PFAS sources (industrial sites, airports, landfills, fire training areas), and wells with a detection are resampled over time. PFAS shares describe wells that were tested for a reason, not every well in the area. In that targeted sampling, 23% of 65 PFOA results in Exeter were above the EPA limit of 4 ng/L. In that targeted sampling, 14% of 65 PFOS results in Exeter were above the EPA limit of 4 ng/L.
Separately, a USGS and NHDES statistical model puts the chance that a bedrock well in Exeter exceeds 5 ug/L of arsenic at 47% (as low as 13% in parts of town), based on geology rather than tests.
What homeowner tests found
NH DHHS WISDOM private well summaries: private wells tested and reported to the state, 2006 to 2020. Shares are against the level the state applies to each contaminant, named in the last column; several are stricter than EPA.
| Contaminant | Wells tested | Above state level | Median | 95th pct | Highest | State level | |
|---|---|---|---|---|---|---|---|
| Sodium | 22 | 64% | 26.4 | 155 | 173 | 20 mg/L | |
| Arsenic | 26 | 46% | 3 | 19.2 | 22.2 | 5 ug/L | |
| Copper (stagnant) | 21 | 10% | 0.1 | 1.9 | 2.7 | 1.3 mg/L | |
| Lead (stagnant) | 22 | 9% | 2.2 | 24.1 | 28.7 | 15 ug/L | |
| Manganese | 22 | 5% | 0 | 300 | 1,300 | 300 ug/L | |
| Fluoride | 54 | 0% | 0.1 | 0.6 | 2.6 | 4 mg/L | |
| Chloride | 26 | 0% | 39 | 114 | 140 | 250 mg/L | |
| Nitrate | 26 | 0% | 1 | 3.7 | 4.7 | 10 mg/L | |
| Nitrite | 26 | 0% | 0 | 0 | 0 | 1 mg/L | |
| Uranium | 22 | 0% | 1 | 6.8 | 15 | 30 ug/L | |
| Iron | 22 | 0% | 0 | 0 | 0 | 300 ug/L |
What individual samples found
Each row summarizes every public sample for that contaminant inside Exeter. Above limit means above the EPA maximum contaminant level; where EPA has no enforceable limit, the row shows a health guideline or nuisance level instead.
| Contaminant | Samples | Detected | Above limit | Median | Highest | Limit | |
|---|---|---|---|---|---|---|---|
| PFOA 2023 | 65 | 72% | 23% | 1.29 | 30.3 | 4 ng/L EPA limit | |
| PFOS 2023 | 65 | 57% | 14% | 0.468 | 21.5 | 4 ng/L EPA limit | |
| PFHxS 2023 | 65 | 65% | 2% | 0.343 | 20.6 | 10 ng/L EPA limit | |
| PFNA 2023 | 65 | 12% | 0% | 0 | 3.52 | 10 ng/L EPA limit |
Sampled fewer than 10 times, too few to summarize: Nitrate (3), Fluoride (1), Sodium (2), Chloride (2), Manganese (1).
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What this means
Among homeowners in Exeter who sent a sample to the state lab, the health-based limits most often exceeded were arsenic (46% of 26 wells), copper (10% of 21 wells), and lead (9% of 22 wells). These are ordinary wells tested by their owners, so the shares are the best available picture of a typical well here, with one caveat: people test more often when they suspect a problem.
Sodium exceeds the state's advisory level in a sizable share of wells; this is mostly a taste, staining or diet issue rather than a toxicity one.
What to test for in Exeter
- Volatile organic compounds (VOCs)28 leaking underground storage tank sites on record locally.
- PFAS3 unlined landfills on record locally.
- Metals panel14 hazardous waste sites on record locally.
- Sodium64% of 22 local wells tested were above the New Hampshire guidance level.
- Arsenic46% of 26 local wells tested were above the New Hampshire guidance level.
- PFOA23% of 65 local samples were above the limit.
- PFOS14% of 65 local samples were above the limit.
- Copper10% of 21 local wells tested were above the New Hampshire guidance level.
- Lead9% of 22 local wells tested were above the New Hampshire guidance level.
- Manganese5% of 22 local wells tested were above the New Hampshire guidance level.
- PFHxS2% of 65 local samples were above the limit.
Wells in Exeter
321 domestic wells in Exeter are on record with the state since 1984. 99% are drilled into bedrock, and the typical well is 302 feet deep (one in ten goes past 540 feet).
In a typical Exeter well, bedrock starts about 16 feet down, the median yield is 10 gallons per minute, 13% of wells yield under 3 gallons per minute and usually need a storage tank.
Bedrock wells are where arsenic, uranium and radon come from: the water sits in fractures in granite and metamorphic rock and picks up whatever the rock carries. That is why testing for those three matters more here than in a dug or gravel well.
Find your own well's report
The state keeps the driller's report for most wells drilled since 1984. It tells you how deep your well is, where bedrock starts, and how much water it makes, which decides what treatment can work.
- Open NHDES OneStop and choose Water Well.
- Enter your town and one word of your street name. Leave out the house number and the Road or Street part; a short search matches more.
- In the results, click Show for your address to see the report: total depth, depth to bedrock, casing, yield in gallons per minute, static water level, and the driller.
- Save Results exports the whole list to a spreadsheet.
Reports exist only for wells drilled since January 1984, when reporting became mandatory, and street names are as they were when the well was drilled.
Contamination sources on record in Exeter
NHDES records 28 leaking underground storage tank sites, 3 unlined landfills, 14 hazardous waste sites, and 9 reported spills and releases in Exeter, among 221 regulated sites in total. Groundwater does not follow property lines, so a well within a few hundred feet of one of these is worth testing for what that site could release.
- 28
- leaking underground storage tank sitesGasoline and heating oil that leaked from tanks move through groundwater as benzene, MTBE and other volatile organic compounds.
- 3
- unlined landfillsOlder unlined landfills are a leading source of PFAS, VOCs and metals in nearby wells.
- 14
- hazardous waste sitesSolvents, degreasers and metals from industrial sites can travel far in fractured bedrock.
- 9
- reported spills and releasesMost spills are fuel; a few are solvents or chemicals that reach the water table.
- 51
- registered underground storage tank sitesRegistered tanks are regulated and inspected; they matter most when they are old or near a shallow well.
- 28
- locally identified potential contamination sourcesTowns inventory these (vehicle repair, labs, salt piles, farms) when they draw wellhead protection maps.
- 87
- other remediation projects
- 1
- other solid waste facility
Treatment that fits the local profile
- Arsenic
- Point-of-use reverse osmosis; Adsorptive media (iron-based) whole-house; Anion exchange
- Copper
- Neutralizing filter to raise pH; Point-of-use reverse osmosis
- Lead
- Point-of-use reverse osmosis; Certified lead-removal carbon filter; Neutralizing filter to raise pH and stop leaching
- Sodium
- Point-of-use reverse osmosis; Distillation
- PFOA
- Granular activated carbon whole-house; Point-of-use reverse osmosis; Anion exchange
- PFOS
- Granular activated carbon whole-house; Point-of-use reverse osmosis; Anion exchange
Book a free water test in Exeter
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Common questions
How deep are wells in Exeter?
The typical domestic well in Exeter is 302 feet deep, based on 321 wells reported to the state since 1984. One in ten is deeper than 540 feet. 99% are drilled into bedrock.
How often should I test a private well in Exeter?
Test for bacteria and nitrate every year. Test once for arsenic, uranium, radon, fluoride, manganese and PFAS, then again every three to five years or after any change in taste, color, or plumbing.
Sources
- NHDES PFAS sampling: 260 samples in Exeter. PFAS results for private wells from the New Hampshire Department of Environmental Services Environmental Monitoring Database. Retrieved September 3, 2026.
- USGS Water Quality Portal: 9 samples in Exeter. Data from the Water Quality Portal, a service of USGS, EPA and USDA; groundwater samples collected by USGS and cooperators. Retrieved September 3, 2026.
- NH DHHS WISDOM private well summaries: summaries for 11 contaminants in Exeter, up to 54 wells each. Town summaries of private well tests run by the New Hampshire Public Health Laboratories, published by NH DHHS through the WISDOM environmental public health tracking portal. Exceedance shares use New Hampshire guidance levels, which are stricter than EPA for arsenic (5 ug/L), manganese (0.3 mg/L), radon (2,000 pCi/L) and sodium (20 mg/L). Statistics for small counts are suppressed (*). Retrieved September 3, 2026.
- NHDES Water Well Inventory: 677 well records in Exeter, 321 domestic. Well construction records reported to the New Hampshire Department of Environmental Services Water Well Board. Only aggregates are shown; owner names and addresses are never stored. Retrieved September 3, 2026.
- NHDES OneStop regulated sites: 221 regulated sites located in Exeter. Remediation sites, underground storage tanks, solid waste facilities and potential contamination sources from the New Hampshire Department of Environmental Services OneStop database. Retrieved September 3, 2026.
Non-detects count as samples and are treated as zero when computing medians. Exactly at the limit counts as not above it. A sample belongs to the town containing the well's reported coordinates.