Well water in Derry, New Hampshire

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Testing strongly recommended

private wells tested between 2006 and 2020 in Derry had lead above the New Hampshire guidance level (15 ug/L), according to NH DHHS.

172 private wells tested 2006 to 2020 in state summaries; 118 test results across 16 contaminants from at least 17 wells, 1963 to 2022; manganese has the most at 18. Data refreshed September 3, 2026.

Compiled by Nick at Well Water Nerd from public records. How these pages are built

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.

Separately, a USGS and NHDES statistical model puts the chance that a bedrock well in Derry exceeds 5 ug/L of arsenic at 33% (as low as 9% 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	Above state level	Wells tested	Median	95th pct	Highest	State level
Radon	69%	42	2,856	34669	56,070	2,000 pCi/L
Sodium	53%	102	23.3	132	371	20 mg/L
Lead (stagnant)	38%	68	8.5	95.6	15,100	15 ug/L
Copper (stagnant)	22%	68	0.3	3.8	27.7	1.3 mg/L
Arsenic	13%	106	0.7	6.8	41	5 ug/L
Iron	11%	104	0	700	7,000	300 ug/L
Chloride	6%	109	59	282	540	250 mg/L
Uranium	6%	103	1.6	37	185	30 ug/L
Manganese	5%	102	0	300	4,300	300 ug/L
Nitrate	2%	91	0.7	6.6	17	10 mg/L
Fluoride	0%	172	0.1	1	3	4 mg/L
Nitrite	0%	91	0	0	0.1	1 mg/L

What individual samples found

Each row summarizes every public sample for that contaminant inside Derry. 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
Arsenic 1986 to 2021	20%	10	60%	1.8	14	10 ug/L EPA limit
Fluoride 1963 to 1990	7%	14	64%	0.15	5.6	4 mg/L EPA limit
Nitrate 1963 to 1990	0%	13	38%	0	7.3	10 mg/L EPA limit
Manganese 1963 to 2021	no limit	18	78%	70	2,150	300 ug/L health guideline
Iron 1963 to 2012	no limit	17	82%	100	5,400	300 ug/L nuisance level
Chloride 1963 to 1990	no limit	14	79%	16	117	250 mg/L nuisance level
Sodium 1963 to 1990	no limit	12	100%	11	76.7	20 mg/L health guideline

Sampled fewer than 10 times, too few to summarize: Lead (5), Uranium (4), Copper (2), Radium (226 + 228) (1), PFOA (1), PFOS (1), PFNA (1), PFHxS (1), Radon (4).

Closer than the town

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 address

What this means

Among homeowners in Derry who sent a sample to the state lab, the health-based limits most often exceeded were lead (38% of 68 wells), copper (22% of 68 wells), and arsenic (13% of 106 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 69% of 42 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 Derry

1
Lead
38% of 68 local wells tested were above the New Hampshire guidance level.
2
Radon
69% of 42 local wells tested were above the New Hampshire guidance level.
3
Copper
22% of 68 local wells tested were above the New Hampshire guidance level.
4
Arsenic
20% of 10 local samples were above the limit.
5
Fluoride
7% of 14 local samples were above the limit.
6
Uranium
6% of 103 local wells tested were above the New Hampshire guidance level.
7
Nitrate
2% of 91 local wells tested were above the New Hampshire guidance level.
8
Coliform bacteria
Recommended for every private well, every year.
9
Volatile organic compounds (VOCs)
25 leaking underground storage tank sites on record locally.
10
PFAS
2 unlined landfills on record locally.
11
Metals panel
10 hazardous waste sites on record locally.

Test your Derry well for lead, radon 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 $209 Already 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 Derry numbers, $29. Every line explained, ranked by what matters, with the fix for each.

Wells in Derry

1,805 domestic wells in Derry are on record with the state since 1984. 99% are drilled into bedrock, and the typical well is 320 feet deep (one in ten goes past 700 feet).

In a typical Derry well, bedrock starts about 12 feet down, the median yield is 8 gallons per minute, 16% 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.

522

1980s

521

1990s

395

2000s

277

2010s

2020s

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 Derry

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 town 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.

Private Wells, NHDES
New Hampshire Environmental Laboratory Accreditation Program, NHDES

Contamination sources on record in Derry

NHDES records 25 leaking underground storage tank sites, 2 unlined landfills, 10 hazardous waste sites, and 28 reported spills and releases in Derry, among 338 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.

25: leaking underground storage tank sitesGasoline and heating oil that leaked from tanks move through groundwater as benzene, MTBE and other volatile organic compounds.
2: unlined landfillsOlder unlined landfills are a leading source of PFAS, VOCs and metals in nearby wells.
10: hazardous waste sitesSolvents, degreasers and metals from industrial sites can travel far in fractured bedrock.
28: reported spills and releasesMost spills are fuel; a few are solvents or chemicals that reach the water table.
70: registered underground storage tank sitesRegistered tanks are regulated and inspected; they matter most when they are old or near a shallow well.
49: locally identified potential contamination sourcesTowns inventory these (vehicle repair, labs, salt piles, farms) when they draw wellhead protection maps.
148: other remediation projects
6: other solid waste facilities

Treatment that fits the local profile

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

Arsenic

Point-of-use reverse osmosis; Adsorptive media (iron-based) whole-house; Anion exchange

Uranium

Point-of-use reverse osmosis; Anion exchange; Whole-house anion exchange

Radon

Aeration (bubble-up or diffused) whole-house; Granular activated carbon whole-house (lower levels only)

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 lead

Under-sink reverse osmosis system

under-sink or countertop, about $300

Look for NSF/ANSI 58 certification listing the contaminant you need removed.

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 lead

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 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.

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Common questions

How deep are wells in Derry?

The typical domestic well in Derry is 320 feet deep, based on 1,805 wells reported to the state since 1984. One in ten is deeper than 700 feet. 99% are drilled into bedrock.

Is there arsenic in well water in Derry?

Arsenic was detected in 60% of 10 public well samples in Derry, and 20% 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 often should I test a private well in Derry?

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 near Derry

Closest first. Groundwater does not stop at a line on a map, so the next town 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: 114 samples in Derry. Data from the Water Quality Portal, a service of USGS, EPA and USDA; groundwater samples collected by USGS and cooperators. Retrieved September 3, 2026.
NHDES PFAS sampling: 4 samples in Derry. PFAS results for private wells from the New Hampshire Department of Environmental Services Environmental Monitoring Database. Retrieved September 3, 2026.
NH DHHS WISDOM private well summaries: summaries for 12 contaminants in Derry, up to 172 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.
NH DHHS WISDOM private well summaries: modeled chance (33%) that a well in Derry exceeds 5 ug/L of arsenic, from geology rather than tests. 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. Retrieved September 3, 2026.
NHDES Water Well Inventory: 1,924 well records in Derry, 1,805 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: 338 regulated sites located in Derry. 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.