Well water in Aroostook County, Maine

In Aroostook County, 4% of 1,087 private wells tested had nitrate above the Maine guideline (10 mg/L), according to Maine CDC.

The strongest signal is PFOS: 12% of 113 local samples were above the limit, too few samples to carry the headline but first on the test list below.

1,089 private wells tested in state summaries; 908 test results across 10 contaminants from at least 113 wells, 1953 to 2026; PFOS has the most at 113. Data refreshed September 15, 2026.

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

Maine DEP samples private wells near fields where sludge or septage was spread and near other known PFAS sources, and resamples detections. PFAS shares describe wells that were tested for a reason, not every well in the area. In that targeted sampling, 12% of 113 PFOS results in Aroostook County were above the EPA limit of 4 ng/L. In that targeted sampling, 12% of 113 PFOA results in Aroostook County were above the EPA limit of 4 ng/L.

An estimated 36,928 people in Aroostook County get their drinking water from a private well, per USGS 2015 county water use. That is about 54% of residents.

Separately, the USGS national arsenic model estimates that 26% of the 36,928 people on private wells in Aroostook County draw water above 10 ug/L (the model's range is 21% to 31%), from geology and well depth rather than local tests.

What homeowner tests found

Maine Tracking Network private well summaries: private wells tested and reported to the state. 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	State level
Nitrate	4%	1,087	10 mg/L
Arsenic	3%	844	10 ug/L
Manganese	2%	860	300 ug/L
Uranium	<1%	772	30 ug/L
Nitrite	<1%	1,089	1 mg/L
Fluoride	0%	951	2 mg/L

What individual samples found

Each row summarizes every public sample for that contaminant inside Aroostook 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
PFOS 2019 to 2026	12%	113	35%	0	32.5	4 ng/L EPA limit
PFOA 2019 to 2026	12%	113	36%	0	44.8	4 ng/L EPA limit
Nitrate 1953 to 1988	8%	64	92%	1.7	31	10 mg/L EPA limit
PFHxS 2019 to 2026	<1%	113	23%	0	10.4	10 ng/L EPA limit
PFNA 2019 to 2026	0%	113	9%	0	2.51	10 ng/L EPA limit
Fluoride 1953 to 1992	0%	71	52%	0	0.4	4 mg/L EPA limit
Chloride 1953 to 1992	no limit	88	97%	9.25	98	250 mg/L nuisance level
Iron 1956 to 1992	no limit	88	82%	110	310,000	300 ug/L nuisance level
Manganese 1956 to 1992	no limit	85	71%	100	55,000	300 ug/L health guideline
Sodium 1953 to 1992	no limit	60	100%	3.4	29	20 mg/L health guideline

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 address

What this means

Among homeowners in Aroostook County who sent a sample to the state lab, the health-based limits most often exceeded were nitrate (4% of 1,087 wells), arsenic (3% of 844 wells), and uranium (<1% of 772 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.

What to test for in Aroostook County

1
PFOS
12% of 113 local samples were above the limit.
2
PFOA
12% of 113 local samples were above the limit.
3
Nitrate
8% of 64 local samples were above the limit.
4
Arsenic
3% of 844 local wells tested were above the Maine guideline.
5
PFHxS
<1% of 113 local samples were above the limit.
6
Uranium
<1% of 772 local wells tested were above the Maine guideline.
7
Nitrite
<1% of 1,089 local wells tested were above the Maine guideline.
8
Coliform bacteria
Recommended for every private well, every year.
9
Volatile organic compounds (VOCs)
119 leaking underground storage tank sites on record locally.
10
PFAS
49 unlined landfills on record locally.
11
Metals panel
30 hazardous waste sites on record locally.

Test your Aroostook County well for PFOS, PFOA and nitrate

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 Maine: certified labs, state programs and prices.

Already have results back? Get your lab report read against the Aroostook County numbers, $29. Every line explained, ranked by what matters, with the fix for each.

Wells in Aroostook County

2,396 domestic wells in Aroostook County are on record with the state since 1975. 96% are drilled into bedrock, and the typical well is 175 feet deep (one in ten goes past 300 feet).

In a typical Aroostook County well, bedrock starts about 12 feet down, the median yield is 12 gallons per minute, 5% 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.

1970s

225

1980s

870

1990s

466

2000s

291

2010s

494

2020s

The rock under Aroostook 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 Maine

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 Well Water, Maine CDC
Laboratory Accreditation, Maine CDC

Contamination sources on record in Aroostook County

Maine DEP records 119 leaking underground storage tank sites, 49 unlined landfills, and 30 hazardous waste sites in Aroostook County, among 427 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.

119: leaking underground storage tank sitesGasoline and heating oil that leaked from tanks move through groundwater as benzene, MTBE and other volatile organic compounds.
49: unlined landfillsOlder unlined landfills are a leading source of PFAS, VOCs and metals in nearby wells.
30: hazardous waste sitesSolvents, degreasers and metals from industrial sites can travel far in fractured bedrock.
229: other remediation projects

Treatment that fits the local profile

PFOS

Granular activated carbon whole-house; Point-of-use reverse osmosis; Anion exchange

PFOA

Granular activated carbon whole-house; Point-of-use reverse osmosis; Anion exchange

Nitrate

Point-of-use reverse osmosis; Anion exchange; Distillation

PFHxS

Granular activated carbon whole-house; Point-of-use reverse osmosis; Anion exchange

Iron

Oxidizing filter whole-house; Water softener (low levels); Aeration plus filtration

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 PFOS

Under-sink reverse osmosis system

under-sink or countertop, about $300

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

For PFOS

Whole-house PFAS carbon system

whole-house, at the point of entry, about $3,000

Granular activated carbon certified to NSF/ANSI 53 for PFOA and PFOS; replace media on schedule.

For PFOS

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 PFOA

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 PFOA

Aquasana HealthShield whole-house filter

whole-house, at the point of entry, about $2,099

Whole-house carbon system the maker certifies to reduce PFAS (PFOA and PFOS) and VOCs at every tap; a UV option adds bacteria protection.

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 Aroostook County

No water treatment company serves Aroostook County through Well Water Nerd yet. We are signing licensed companies on county by county: they test at your tap for free, walk you through the numbers, and quote treatment only if something needs fixing. Leave your details and you are first in line. Nothing is shared until a company joins for Aroostook County, and you get an email naming it first.

Common questions

How deep are wells in Aroostook County?

The typical domestic well in Aroostook County is 175 feet deep, based on 2,396 wells reported to the state since 1975. One in ten is deeper than 300 feet. 96% are drilled into bedrock.

How often should I test a private well in Aroostook 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 Aroostook County

61 towns have fewer than 30 public samples and are included in the Aroostook County totals above rather than shown separately: Allagash, Amity, Ashland, Bancroft UT, Blaine, Bridgewater, Castle Hill, Caswell, Central Aroostook UT, Chapman, Connor UT, Crystal, Cyr plantation, Dyer Brook, Eagle Lake, Easton, Frenchville, Garfield plantation, Glenwood plantation, Grand Isle, Hamlin, Hammond, Haynesville, Hersey, Limestone, Linneus, Littleton, Ludlow, Macwahoc plantation, Mars Hill, Masardis, Merrill, Monticello, Moro plantation, Nashville plantation, New Canada, New Limerick, New Sweden, Northwest Aroostook UT, Oakfield, Orient, Penobscot Indian Island Reservation, Perham, Portage Lake, Reed plantation, Sherman, Smyrna, South Aroostook UT, Square Lake UT, St. Agatha, St. Francis, St. John plantation, Stockholm, Van Buren, Wade, Wallagrass, Washburn, Westfield, Westmanland, Weston, Winterville plantation.

Counties near Aroostook 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 Maine dataset as CSV, every county and town, with the sources named.

Sources

USGS Water Quality Portal: 456 samples in Aroostook 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.
Maine DEP PFAS investigation: 452 samples in Aroostook County. PFAS results for private wells sampled by the Maine Department of Environmental Protection. Retrieved September 3, 2026.
Maine Tracking Network private well summaries: summaries for 6 contaminants in Aroostook County, up to 1,089 wells each. Town summaries of private well tests run by the Maine Health and Environmental Testing Laboratory, published by Maine CDC through the Maine Tracking Network. Shares are against Maine's guideline for each analyte (arsenic 10 ug/L, uranium 30 ug/L, fluoride 2 mg/L, manganese 0.3 mg/L, nitrate 10 mg/L, nitrite 1 mg/L). Towns with too few tests are suppressed (NR). Only the share above the guideline and wells tested are published; no medians. Retrieved September 3, 2026.
USGS national arsenic model (Ayotte 2017): estimated share of 36,928 people on private wells in Aroostook 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.
Maine Geological Survey well database: 3,445 well records in Aroostook County, 2,396 domestic. Well construction records reported to the Maine Geological Survey by licensed well drillers. Only aggregates are shown; owner names and addresses are never stored. Retrieved September 3, 2026.
Maine DEP regulated sites: 427 regulated sites located in Aroostook County. Remediation sites, leaking underground storage tanks and closed municipal landfills from the Maine Department of Environmental Protection. 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.