Well water in Carroll County, New Hampshire
1in4
Testing strongly recommended
private wells tested between 2006 and 2020 in Carroll County had arsenic above the New Hampshire guidance level (5 ug/L), according to NH DHHS.
1,910 private wells tested 2006 to 2020 in state summaries; 1,916 test results across 15 contaminants from at least 224 wells, 1966 to 2022; nitrate has the most at 355. Data refreshed September 15, 2026.
Compiled by Nick at Well Water Nerd from public records. How these pages are built
An estimated 21,941 people in Carroll County get their drinking water from a private well, per NH DHHS WISDOM, BRFSS 2020. That is about 64% of residents (survey range 57% to 71%).
Separately, the USGS national arsenic model estimates that 3% of the 16,513 people on private wells in Carroll County draw water above 10 ug/L (the model's range is 2% to 4%), from geology and well depth rather than local 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. County and state figures combine the town summaries, weighted by wells tested; medians are not combined.
| Contaminant | Above state level | Wells tested | Median | 95th pct | Highest | State level |
|---|---|---|---|---|---|---|
| Radon | 673 | 150,000 | 2,000 pCi/L | |||
| Sodium | 1,627 | 699 | 20 mg/L | |||
| Arsenic | 1,741 | 489 | 5 ug/L | |||
| Iron | 1,639 | 13,600 | 300 ug/L | |||
| Lead (stagnant) | 1,491 | 3,820 | 15 ug/L | |||
| Copper (stagnant) | 1,488 | 18.2 | 1.3 mg/L | |||
| Uranium | 1,701 | 420 | 30 ug/L | |||
| Fluoride | 1,910 | 15 | 4 mg/L | |||
| Manganese | 1,636 | 10,600 | 300 ug/L | |||
| Chloride | 1,832 | 1,300 | 250 mg/L | |||
| Nitrate | 1,819 | 40 | 10 mg/L | |||
| Nitrite | 1,819 | 0.2 | 1 mg/L |
What individual samples found
Each row summarizes every public sample for that contaminant inside Carroll County. 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 | Above limit | Samples | Detected | Median | Highest | Limit |
|---|---|---|---|---|---|---|
| Fluoride 1966 to 2021 | 210 | 90% | 1.2 | 18.7 | 4 mg/L EPA limit | |
| Uranium 2000 to 2022 | 31 | 94% | 0.898 | 52.7 | 30 ug/L EPA limit | |
| Copper 1986 to 2022 | 69 | 42% | 0 | 6.91 | 1.3 mg/L EPA limit | |
| Arsenic 1986 to 2022 | 79 | 20% | 0 | 160 | 10 ug/L EPA limit | |
| Nitrate 1966 to 2021 | 355 | 61% | 0.1 | 14 | 10 mg/L EPA limit | |
| Lead 1986 to 2022 | 69 | 36% | 0 | 5.69 | 15 ug/L EPA limit | |
| Radium (226 + 228) 1986 to 2019 | 15 | 73% | 0 | 1 | 5 pCi/L EPA limit | |
| Chloride 1966 to 2021 | no limit | 275 | 77% | 5 | 654 | 250 mg/L nuisance level |
| Manganese 1966 to 2022 | no limit | 270 | 69% | 20 | 2,500 | 300 ug/L health guideline |
| Iron 1966 to 2021 | no limit | 253 | 72% | 100 | 74,000 | 300 ug/L nuisance level |
| Sodium 1966 to 2021 | no limit | 247 | 96% | 9 | 390 | 20 mg/L health guideline |
| Radon 1986 to 2001 | no limit | 35 | 100% | 3,800 | 83,600 | 2,000 pCi/L health guideline |
Sampled fewer than 10 times, too few to summarize: E. coli (4), PFOA (2), PFOS (2).
Over time
Share of samples above the limit by period. A cell needs ten samples to show; a comparison needs twenty in each period. Later periods sample fewer wells, and often the ones already known to have a problem.
| Contaminant | before 2000 | 2000s | 2010s | 2020s |
|---|---|---|---|---|
| Nitrate | 1%332 samples | 0%10 samples | 0%10 samples | n/a |
| Arsenic | 2%48 samples | n/a | n/a | 0%21 samples |
| Copper | 0%38 samples | n/a | n/a | 10%21 samples |
| Lead | 0%38 samples | n/a | n/a | 0%21 samples |
Copper above the limit in Carroll County rose from 0% of 38 samples before 2000 to 10% of 21 in the 2020s.
Arsenic, lead have held within a few points between the two most recent periods with enough samples.
Closer than the county
See the sampled wells near your address
The same records, drawn around one point: which wells within a few miles were sampled and what they found, how deep the wells next to you were drilled, and any leaking tank or cleanup site within a mile.
Check my addressWhat this means
Among homeowners in Carroll County who sent a sample to the state lab, the health-based limits most often exceeded were arsenic (26% of 1,741 wells), lead (14% of 1,491 wells), and copper (14% of 1,488 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.
Radon was above the New Hampshire guidance level of 2,000 pCi/L in 33% of 673 wells. Radon in water matters because it moves into indoor air during showers and laundry.
Sodium and iron exceed the state's advisory level in a sizable share of wells; these are mostly a taste, staining or diet issue rather than a toxicity one.
What to test for in Carroll County
- 1Arsenic26% of 1,741 local wells tested were above the New Hampshire guidance level.
- 2Lead14% of 1,491 local wells tested were above the New Hampshire guidance level.
- 3Copper14% of 1,488 local wells tested were above the New Hampshire guidance level.
- 4Fluoride11% of 210 local samples were above the limit.
- 5Uranium6% of 31 local samples were above the limit.
- 6Nitrate1% of 355 local samples were above the limit.
- 7Radon33% of 673 local wells tested were above the New Hampshire guidance level.
- 8Sodium29% of 1,627 local wells tested were above the New Hampshire guidance level.
- 9Volatile organic compounds (VOCs)112 leaking underground storage tank sites on record locally.
- 10PFAS20 unlined landfills on record locally.
- 11Metals panel21 hazardous waste sites on record locally.
Test your Carroll County well for arsenic, lead and copper
Certified lab analysis of your own tap water, bottles and prepaid return shipping included. The Essential well panel covers arsenic, uranium, nitrate, lead, copper, manganese, iron, sodium and bacteria; radon and PFAS are add-ons.
Order the Tap Score well water test kit, from $209Already tested? Upload the report
Just want bacteria checked first? Tap Score coliform and E. coli test, $99. Coliform and E. coli are the tests every well needs every year.
Want a quick look before paying for a lab? Home well water test strips on Amazon check hardness, iron, pH and nitrate in minutes. They are a screen, not a result: arsenic, bacteria, uranium and PFAS need a certified lab.
Affiliate links: the merchant pays us a commission and the price is the same for you. It does not change what the data above says. As an Amazon Associate we earn from qualifying purchases.
Where to get a well tested in New Hampshire: certified labs, state programs and prices.
Already have results back? Get your lab report read against the Carroll County numbers, $29. Every line explained, ranked by what matters, with the fix for each.
Wells in Carroll County
9,305 domestic wells in Carroll County are on record with the state since 1977. 88% are drilled into bedrock, and the typical well is 400 feet deep (one in ten goes past 740 feet).
In a typical Carroll County well, bedrock starts about 35 feet down, the median yield is 8 gallons per minute, 20% 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.
The rock under Carroll County
Not a principal aquifer
The USGS map places this area outside any principal aquifer, which usually means wells here draw from fractured bedrock or thin local deposits rather than a large regional aquifer. Bedrock wells of that kind are where arsenic, radon and uranium turn up, and yields vary from well to well.
Classification from the USGS Principal Aquifers of the United States (national map, 2003 edition, GIS release 2015), read at the county centroid. A single well can sit in a different unit, especially near a boundary.
Official help in New Hampshire
Two places to start that are not selling anything: the state program that answers private well questions, and its list of labs certified to run drinking water tests. A certified lab is the difference between a result you can act on and a number.
Contamination sources on record in Carroll County
NHDES records 112 leaking underground storage tank sites, 20 unlined landfills, 21 hazardous waste sites, and 67 reported spills and releases in Carroll County, among 1,294 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.
- 112
- leaking underground storage tank sitesGasoline and heating oil that leaked from tanks move through groundwater as benzene, MTBE and other volatile organic compounds.
- 20
- unlined landfillsOlder unlined landfills are a leading source of PFAS, VOCs and metals in nearby wells.
- 21
- hazardous waste sitesSolvents, degreasers and metals from industrial sites can travel far in fractured bedrock.
- 67
- reported spills and releasesMost spills are fuel; a few are solvents or chemicals that reach the water table.
- 283
- registered underground storage tank sitesRegistered tanks are regulated and inspected; they matter most when they are old or near a shallow well.
- 108
- locally identified potential contamination sourcesTowns inventory these (vehicle repair, labs, salt piles, farms) when they draw wellhead protection maps.
- 1
- lined landfill or transfer facility
- 660
- other remediation projects
- 22
- other solid waste facilities
Treatment that fits the local profile
Arsenic
Point-of-use reverse osmosis; Adsorptive media (iron-based) whole-house; Anion exchange
Lead
Point-of-use reverse osmosis; Certified lead-removal carbon filter; Neutralizing filter to raise pH and stop leaching
Copper
Neutralizing filter to raise pH; Point-of-use reverse osmosis
Radon
Aeration (bubble-up or diffused) whole-house; Granular activated carbon whole-house (lower levels only)
Sodium
Point-of-use reverse osmosis; Distillation
Fluoride
Point-of-use reverse osmosis; Activated alumina; Distillation
Systems we would look at first
Some links below are affiliate links. If you buy through one, the merchant pays us a commission at no extra cost to you. It does not change which products we list or what the data says.
For arsenic
Under-sink reverse osmosis system
under-sink or countertop, about $300
Look for NSF/ANSI 58 certification listing the contaminant you need removed.
For arsenic
Whole-house arsenic and uranium filter
whole-house, at the point of entry, about $2,500
Adsorptive iron-based media; sized to your well yield.
For arsenic
Aquasana SmartFlow reverse osmosis
under-sink or countertop, about $225
Certified to NSF/ANSI 58 and 53 to reduce arsenic (96%, pentavalent), fluoride (90%), lead (99%), nitrate, nitrite and PFOA/PFOS at the kitchen tap, with a remineralizer.
For lead
Aquasana Claryum 3-Stage under-sink filter
under-sink or countertop, about $175
Certified to NSF/ANSI 53 to reduce 99% of lead and 99.7% of PFOA and PFOS at the tap. Not a fix for arsenic, nitrate or bacteria.
For lead
Acid neutralizing filter
whole-house, at the point of entry, about $1,200
Raises pH so plumbing stops leaching lead and copper.
For iron
Iron and manganese oxidizing filter
whole-house, at the point of entry, about $1,800
Air-injection or greensand media; fixes staining at the source.
Free, no obligation
Get on the list for a free in-home water test in Carroll County
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Common questions
How deep are wells in Carroll County?
The typical domestic well in Carroll County is 400 feet deep, based on 9,305 wells reported to the state since 1977. One in ten is deeper than 740 feet. 88% are drilled into bedrock.
Is there arsenic in well water in Carroll County?
Arsenic was detected in 20% of 79 public well samples in Carroll County, and 1% were above the EPA limit of 10 ug/L. Arsenic has no taste or smell; a lab test is the only way to know your level.
How high is radon in well water in Carroll County?
The median radon level across 35 public samples in Carroll County was 3,800 pCi/L, with a high of 83,600 pCi/L. New Hampshire recommends treatment above 2,000 pCi/L.
How often should I test a private well in Carroll County?
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.
Towns in Carroll County
- AlbanyUSGS estimate
- Bartlett6% fluoride
- BrookfieldUSGS estimate
- ChathamUSGS estimate
- Conway32% uranium
- EatonUSGS estimate
- Effingham34% copper
- Freedom16% lead
- Hale's locationUSGS estimate
- Hart's LocationUSGS estimate
- Jackson20% arsenic
- Madison27% copper
- Moultonborough39% arsenic
- Ossipee20% copper
- Sandwich14% copper
- Tamworth19% copper
- Tuftonboro41% arsenic
- Wakefield20% copper
- Wolfeboro42% arsenic
Counties near Carroll County
Closest first. Groundwater does not stop at a line on a map, so the next county over is a fair second opinion.
Want the numbers themselves? Download the New Hampshire dataset as CSV, every county and town, with the sources named.
Sources
- USGS Water Quality Portal: 1,916 samples in Carroll County. 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 12 contaminants in Carroll County, up to 1,910 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.
- USGS national arsenic model (Ayotte 2017): estimated share of 16,513 people on private wells in Carroll County above 10 ug/L of arsenic, from geology, well depth and land use. County estimates of domestic well users with arsenic above 10 ug/L from the USGS national logistic regression model (Ayotte, Medalie and Qi, 2017), with private well population from the USGS 2015 county water-use compilation (Dieter and others, 2018). Retrieved September 15, 2026.
- NHDES Water Well Inventory: 10,192 well records in Carroll County, 9,305 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: 1,294 regulated sites located in Carroll County. 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.