Well water in North Carolina

1in10

Testing recommended

tested well samples in North Carolina exceeded the EPA limit for nitrate (10 mg/L), based on public data from USGS Water Quality Portal.

110,409 private wells tested 1998 to 2019 in state summaries; 32,467 test results across 15 contaminants from at least 3,234 wells, 1932 to 2024; nitrate has the most at 6,130. Data refreshed September 15, 2026.

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

An estimated 2,407,661 people in North Carolina get their drinking water from a private well, per USGS 2015 county water use.

Separately, the USGS national arsenic model estimates that 5% of the 2,407,661 people on private wells in North Carolina draw water above 10 ug/L (the model's range is 3% to 8%), from geology and well depth rather than local tests.

What homeowner tests found

NCWELL private well summaries: private wells tested and reported to the state, 1998 to 2019. 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	Highest	State level
Iron	29%	65,654	221,000,000	300 ug/L
Manganese	24%	110,182	46,300	50 ug/L
Uranium	9%	580	1,970	30 ug/L
Lead	3%	110,409	105,440	15 ug/L
Arsenic	2%	110,383	806	10 ug/L
Nitrate	<1%	46,033	150	10 mg/L
Copper	<1%	65,754	277	1 mg/L
Nitrite	<1%	46,031	2.1	1 mg/L

What individual samples found

Each row summarizes every public sample for that contaminant inside North Carolina. 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
Nitrate 1932 to 2024	11%	6,130	69%	0.1	664	10 mg/L EPA limit
Arsenic 1980 to 2024	7%	1,659	41%	0	690	10 ug/L EPA limit
E. coli 1997 to 2022	5%	229	5%	0	52	0 MPN/100mL EPA limit
Lead 1971 to 2024	3%	1,606	62%	0	2,800	15 ug/L EPA limit
Fluoride 1941 to 2024	<1%	4,140	71%	0.1	1,300	4 mg/L EPA limit
Uranium 1994 to 2024	<1%	476	49%	0	44.2	30 ug/L EPA limit
Copper 1949 to 2024	<1%	1,670	42%	0	8.76	1.3 mg/L EPA limit
Radium (226 + 228) 1994 to 2022	<1%	444	67%	0.079	7.5	5 pCi/L EPA limit
PFOA 2021 to 2022	0%	26	0%	0	0	4 ng/L EPA limit
PFOS 2021 to 2022	0%	25	0%	0	0	4 ng/L EPA limit
Iron 1932 to 2024	no limit	5,596	90%	300	588,000	300 ug/L nuisance level
Chloride 1932 to 2024	no limit	3,897	100%	8.87	10,400	250 mg/L nuisance level
Sodium 1932 to 2024	no limit	3,187	100%	11.2	119,000	20 mg/L health guideline
Manganese 1943 to 2024	no limit	3,010	92%	38	46,800	300 ug/L health guideline
Radon 1994 to 2014	no limit	372	99%	640	18,600	2,000 pCi/L health guideline

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	7%3,962 samples	25%1,418 samples	4%608 samples	4%142 samples
Fluoride	<1%3,218 samples	0%563 samples	0%287 samples	0%72 samples
Copper	<1%1,242 samples	0%218 samples	0%137 samples	0%73 samples
Arsenic	9%1,143 samples	4%306 samples	1%137 samples	1%73 samples
Lead	4%1,183 samples	<1%212 samples	2%138 samples	3%73 samples
Uranium	0%44 samples	<1%226 samples	0%135 samples	0%71 samples

Nitrate, fluoride, copper, arsenic, lead, uranium have held within a few points between the two most recent periods with enough samples.

North Carolina counties side by side

The share of wells over the drinking water limit in each county, which is the federal limit unless the state sets a stricter one (New Hampshire and New Jersey hold arsenic to 5 µg/L, half the federal 10). Highest for arsenic: Union, 19% of 5,154 wells. Figures marked "wells" come from North Carolina's homeowner testing program, a broad cross-section of wells; figures marked "samples" are public samples, which lean toward wells already suspected of a problem. Each county page names the source, record and dates. Click a column to sort.


Union	19% of 5,154 wells	2% of 5,140 wells	1% of 1,550 wells	<1% of 2,354 wells	5,154
Anson	19% of 132 wells	5% of 131 wells	3% of 37 wells	1% of 77 wells	132
Stanly	18% of 1,278 wells	2% of 1,239 wells	2% of 481 wells	0% of 604 wells	1,278
Montgomery	8% of 576 wells	8% of 576 wells	1% of 207 wells	0% of 282 wells	576
Alexander	6% of 272 wells	<1% of 272 wells	0% of 120 wells	0% of 169 wells	272
Randolph	5% of 2,619 wells	3% of 2,611 wells	2% of 853 wells	<1% of 1,288 wells	2,619
Currituck	5% of 1,130 wells	1% of 1,130 wells	1% of 1,015 wells	0% of 1,031 wells	1,130
Davidson	5% of 697 wells	3% of 695 wells	<1% of 193 wells	<1% of 291 wells	697
Lincoln	4% of 2,333 wells	1% of 2,325 wells	1% of 1,276 wells	<1% of 1,665 wells	2,333
Lee	4% of 278 wells	3% of 278 wells	0% of 83 wells	0% of 184 wells	278
Moore	3% of 1,280 wells	7% of 1,289 wells	2% of 474 wells	<1% of 699 wells	1,289
Cabarrus	3% of 1,382 wells	1% of 1,388 wells	<1% of 594 wells	<1% of 855 wells	1,388
Cumberland	3% of 2,044 wells	7% of 1,970 wells	2% of 1,165 wells	<1% of 1,414 wells	2,044
Richmond	3% of 524 wells	7% of 523 wells	9% of 323 wells	<1% of 317 wells	524
Catawba	3% of 1,567 wells	1% of 1,527 wells	0% of 30 wells	<1% of 1,204 wells	1,567
Gaston	3% of 2,764 wells	2% of 2,763 wells	2% of 812 wells	<1% of 1,672 wells	2,764
Chatham	3% of 3,129 wells	2% of 3,128 wells	2% of 1,761 wells	<1% of 2,071 wells	3,129
Cleveland	3% of 390 wells	3% of 392 wells	0% of 79 wells	1% of 177 wells	392
Rockingham	3% of 986 wells	2% of 986 wells	1% of 645 wells	<1% of 607 wells	986
Person	2% of 1,804 wells	3% of 1,802 wells	<1% of 937 wells	<1% of 1,215 wells	1,804
Harnett	2% of 368 wells	5% of 367 wells	3% of 115 wells	0% of 206 wells	368
Transylvania	2% of 580 wells	3% of 580 wells	0% of 352 wells	<1% of 381 wells	580
Watauga	2% of 1,077 wells	4% of 1,065 wells	<1% of 279 wells	1% of 662 wells	1,077
Caldwell	2% of 358 wells	2% of 357 wells	no data	0% of 312 wells	358
Dare	2% of 462 wells	5% of 462 wells	2% of 50 wells	<1% of 223 wells	462
Perquimans	2% of 52 wells	2% of 52 wells	0% of 40 wells	0% of 47 wells	52
Northampton	2% of 446 wells	2% of 446 wells	5% of 113 wells	0% of 244 wells	446
Nash	2% of 2,258 wells	3% of 2,258 wells	<1% of 1,239 wells	0% of 1,409 wells	2,258
New Hanover	1% of 2,108 wells	2% of 2,172 wells	<1% of 763 wells	3% of 1,018 wells	2,172
Wilson	1% of 465 wells	2% of 465 wells	1% of 346 wells	<1% of 373 wells	465
McDowell	1% of 1,251 wells	4% of 1,250 wells	<1% of 980 wells	<1% of 1,029 wells	1,251
Orange	1% of 7,262 wells	3% of 7,286 wells	<1% of 2,848 wells	<1% of 3,582 wells	7,286
Johnston	1% of 2,003 wells	3% of 2,003 wells	2% of 558 wells	<1% of 922 wells	2,003
Avery	1% of 640 wells	5% of 640 wells	<1% of 418 wells	<1% of 532 wells	640
Forsyth	1% of 369 wells	3% of 367 wells	<1% of 216 wells	<1% of 270 wells	369
Durham	1% of 860 wells	2% of 856 wells	<1% of 353 wells	1% of 500 wells	860
Rutherford	1% of 784 wells	2% of 784 wells	<1% of 522 wells	<1% of 586 wells	784
Rowan	1% of 2,374 wells	3% of 2,378 wells	<1% of 904 wells	<1% of 1,152 wells	2,378
Halifax	<1% of 215 wells	1% of 201 wells	0% of 113 wells	0% of 143 wells	215
Yadkin	<1% of 328 wells	<1% of 329 wells	2% of 229 wells	<1% of 243 wells	329
Mitchell	<1% of 564 wells	2% of 564 wells	0% of 342 wells	<1% of 408 wells	564
Duplin	<1% of 585 wells	1% of 586 wells	2% of 391 wells	<1% of 427 wells	586
Graham	<1% of 454 wells	2% of 454 wells	0% of 117 wells	1% of 237 wells	454
Burke	<1% of 471 wells	1% of 471 wells	2% of 219 wells	0% of 302 wells	471
Guilford	<1% of 4,700 wells	4% of 4,698 wells	<1% of 2,105 wells	<1% of 2,307 wells	4,700
Wilkes	<1% of 678 wells	2% of 678 wells	1% of 502 wells	0% of 518 wells	678
Onslow	<1% of 234 wells	3% of 234 wells	0% of 141 wells	0% of 157 wells	234
Granville	<1% of 1,220 wells	2% of 1,219 wells	<1% of 635 wells	<1% of 867 wells	1,220
Wayne	<1% of 547 wells	5% of 548 wells	3% of 271 wells	0% of 343 wells	548
Ashe	<1% of 717 wells	4% of 717 wells	<1% of 247 wells	<1% of 486 wells	717
Alamance	<1% of 2,583 wells	2% of 2,590 wells	1% of 1,504 wells	<1% of 1,889 wells	2,590
Brunswick	<1% of 826 wells	1% of 826 wells	0% of 519 wells	<1% of 575 wells	826
Columbus	<1% of 1,247 wells	<1% of 1,244 wells	0% of 705 wells	0% of 832 wells	1,247
Wake	<1% of 2,461 wells	3% of 2,466 wells	<1% of 122 wells	1% of 681 wells	2,466
Stokes	<1% of 973 wells	3% of 974 wells	<1% of 653 wells	<1% of 781 wells	974
Swain	<1% of 500 wells	2% of 508 wells	0% of 175 wells	1% of 292 wells	508
Macon	<1% of 2,368 wells	5% of 2,424 wells	0% of 997 wells	2% of 1,847 wells	2,424
Madison	<1% of 1,190 wells	6% of 1,190 wells	0% of 382 wells	<1% of 605 wells	1,190
Surry	<1% of 1,171 wells	4% of 1,171 wells	<1% of 443 wells	<1% of 593 wells	1,171
Cherokee	<1% of 3,031 wells	3% of 3,035 wells	0% of 451 wells	<1% of 1,388 wells	3,035
Sampson	<1% of 1,401 wells	2% of 1,401 wells	7% of 602 wells	<1% of 790 wells	1,401
Henderson	<1% of 1,497 wells	5% of 1,497 wells	0% of 873 wells	2% of 955 wells	1,497
Mecklenburg	<1% of 2,600 wells	3% of 2,593 wells	0% of 93 wells	1% of 1,017 wells	2,600
Carteret	<1% of 973 wells	3% of 987 wells	0% of 538 wells	<1% of 618 wells	987
Yancey	<1% of 1,028 wells	3% of 1,029 wells	<1% of 433 wells	1% of 721 wells	1,029
Buncombe	<1% of 4,904 wells	2% of 4,907 wells	<1% of 2,530 wells	<1% of 3,509 wells	4,907
Clay	<1% of 1,575 wells	2% of 1,575 wells	<1% of 177 wells	<1% of 802 wells	1,575
Franklin	<1% of 1,554 wells	3% of 1,560 wells	1% of 766 wells	<1% of 977 wells	1,560
Iredell	<1% of 1,817 wells	1% of 1,818 wells	<1% of 985 wells	0% of 1,151 wells	1,818
Pender	<1% of 1,614 wells	<1% of 1,614 wells	0% of 1,173 wells	0% of 1,299 wells	1,614
Alleghany	0% of 346 wells	7% of 347 wells	2% of 81 wells	2% of 219 wells	347
Beaufort	0% of 216 wells	2% of 216 wells	0% of 108 wells	<1% of 164 wells	216
Bertie	0% of 104 wells	0% of 104 wells	2% of 62 wells	0% of 79 wells	104
Bladen	0% of 232 wells	<1% of 233 wells	0% of 107 wells	0% of 151 wells	233
Camden	0% of 92 wells	0% of 92 wells	0% of 81 wells	0% of 83 wells	92
Caswell	0% of 688 wells	3% of 688 wells	<1% of 519 wells	2% of 448 wells	688
Chowan	0% of 47 wells	2% of 47 wells	10% of 52 samples	0% of 44 wells	52
Craven	0% of 250 wells	3% of 250 wells	0% of 82 wells	<1% of 145 wells	250
Davie	0% of 493 wells	1% of 493 wells	2% of 98 wells	0% of 218 wells	493
Edgecombe	0% of 264 wells	2% of 264 wells	4% of 97 wells	2% of 135 wells	264
Gates	0% of 41 wells	2% of 41 wells	0% of 34 samples	no data	41
Greene	0% of 63 wells	5% of 64 wells	3% of 30 wells	2% of 42 wells	64
Haywood	0% of 1,994 wells	2% of 1,994 wells	<1% of 676 wells	<1% of 1,152 wells	1,994
Hertford	0% of 110 wells	2% of 110 wells	3% of 60 wells	0% of 73 wells	110
Hoke	0% of 303 wells	13% of 306 wells	2% of 133 wells	<1% of 195 wells	306
Hyde	0% of 80 wells	1% of 80 wells	no data	0% of 56 wells	80
Jackson	0% of 2,423 wells	3% of 2,457 wells	0% of 593 wells	<1% of 1,530 wells	2,457
Jones	0% of 95 wells	1% of 95 wells	0% of 45 samples	0% of 47 wells	95
Lenoir	0% of 170 wells	<1% of 170 wells	3% of 79 wells	0% of 98 wells	170
Martin	0% of 130 wells	2% of 130 wells	0% of 51 wells	1% of 70 wells	130
Pamlico	0% of 175 wells	2% of 175 wells	0% of 95 wells	0% of 129 wells	175
Pasquotank	0% of 54 wells	0% of 54 wells	0% of 63 samples	0% of 47 wells	63
Pitt	0% of 263 wells	<1% of 263 wells	0% of 139 wells	0% of 172 wells	263
Polk	0% of 395 wells	4% of 401 wells	0% of 195 wells	2% of 285 wells	401
Robeson	0% of 195 wells	3% of 198 wells	5% of 61 wells	0% of 106 wells	198
Scotland	0% of 268 wells	6% of 266 wells	2% of 130 wells	<1% of 173 wells	268
Vance	0% of 387 wells	3% of 387 wells	0% of 157 wells	<1% of 228 wells	387
Warren	0% of 292 wells	3% of 292 wells	0% of 47 wells	1% of 152 wells	292
Washington	0% of 102 wells	2% of 102 wells	0% of 40 wells	0% of 74 wells	102

What this means

Among homeowners in North Carolina who sent a sample to the state lab, the health-based limits most often exceeded were uranium (9% of 580 wells), lead (3% of 110,409 wells), and arsenic (2% of 110,383 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.

Iron and manganese 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 North Carolina

1
Nitrate
11% of 6,130 local samples were above the limit.
2
Uranium
9% of 580 local wells tested were above the EPA limit.
3
Arsenic
7% of 1,659 local samples were above the limit.
4
E. coli
5% of 229 local samples were above the limit.
5
Lead
3% of 1,606 local samples were above the limit.
6
Copper
<1% of 65,754 local wells tested were above the North Carolina groundwater standard.
7
Fluoride
<1% of 4,140 local samples were above the limit.
8
Nitrite
<1% of 46,031 local wells tested were above the EPA limit.
9
Volatile organic compounds (VOCs)
39,722 leaking underground storage tank sites on record locally.

Test your North Carolina well for nitrate, uranium and arsenic

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 North Carolina: certified labs, state programs and prices.

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

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Send me the North Carolina report

The numbers above, which tests to order and where, and the treatment that fits the local profile, in one email.

The rock under North Carolina

Northern Atlantic Coastal Plain aquifer system

Semiconsolidated sand. Coastal plain sands like these give steady yields at moderate depth. Salt water and sodium are the usual issues near the coast, and nitrate where the water table is shallow; arsenic and radon from bedrock are less common.

Classification from the USGS Principal Aquifers of the United States (national map, 2003 edition, GIS release 2015), read at the state centroid. A single well can sit in a different unit, especially near a boundary.

Official help in North Carolina

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 Testing FAQs, NCDHHS
NCSLPH - Lab Certification, NCDHHS

Contamination sources on record in North Carolina

NC DEQ records 39,722 leaking underground storage tank sites in North Carolina, among 39,722 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.

39,722: leaking underground storage tank sitesGasoline and heating oil that leaked from tanks move through groundwater as benzene, MTBE and other volatile organic compounds.

Treatment that fits the local profile

Uranium

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

Iron

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

Manganese

Oxidizing filter (greensand, birm) whole-house; Water softener (low levels); Point-of-use reverse osmosis

Nitrate

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

Arsenic

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

E. coli

Shock chlorination and fix the well cap or casing; UV disinfection whole-house; Chlorination system

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 uranium

Under-sink reverse osmosis system

under-sink or countertop, about $300

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

For uranium

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 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.

For nitrate

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 E. coli

UV disinfection system

whole-house, at the point of entry, about $900

Fix the well cap and casing first; UV keeps bacteria from returning.

For E. coli

Aquasana Rhino Well Water with UV

whole-house, at the point of entry, about $2,871

Whole-house system built for wells: sediment pre-filter, KDF and carbon, and a UV lamp rated to kill 99.99% of bacteria and viruses. It does not remove arsenic, nitrate, uranium or radon.

Common questions

Is there arsenic in well water in North Carolina?

Arsenic was detected in 41% of 1,659 public well samples in North Carolina, and 7% 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 North Carolina?

The median radon level across 372 public samples in North Carolina was 640 pCi/L, with a high of 18,600 pCi/L. New Hampshire recommends treatment above 2,000 pCi/L.

How often should I test a private well in North Carolina?

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.

Counties in North Carolina

Tyrrell60 samples

Want the numbers themselves? Download the North Carolina dataset as CSV, every county and town, with the sources named.

Sources

USGS Water Quality Portal: 32,467 samples in North Carolina. Data from the Water Quality Portal, a service of USGS, EPA and USDA; groundwater samples collected by USGS and cooperators. Retrieved September 3, 2026.
NCWELL private well summaries: summaries for 8 contaminants in North Carolina, up to 110,409 wells each. County summaries of private well tests run by the NC State Laboratory of Public Health, 1998 to 2019, compiled by the UNC Superfund Research Program (NCWELL database). Counts are tests, not distinct wells; since 2008 every new well is tested once, so most tests are unique wells. Shares are against the NC 2L groundwater standard where one exists (manganese 50 ug/L, lead 15, iron 300) and otherwise the EPA limit. Medians are not used because more than half of results sit at the reporting limit for most analytes. Retrieved September 9, 2026.
USGS national arsenic model (Ayotte 2017): estimated share of 2,407,661 people on private wells in North Carolina 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.
NC DEQ regulated sites: 39,722 regulated sites located in North Carolina. Underground storage tank incidents from the North Carolina Department of Environmental Quality UST Section. Retrieved September 9, 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.