Well water in North Carolina
In North Carolina, 9% of 580 private wells tested between 1998 and 2019 had uranium above the EPA limit (30 ug/L), according to the NC State Laboratory of Public Health (NCWELL).
110,409 private wells tested 1998 to 2019 in state summaries; 476 individual samples from 343 wells, 1941 to 2024. Data refreshed September 9, 2026.
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.
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 | Samples | Detected | Above limit | Median | Highest | Limit | |
|---|---|---|---|---|---|---|---|
| Nitrate 1943 to 2022 | 190 | 69% | 11% | 0.1 | 169 | 10 mg/L EPA limit | |
| Arsenic 1981 to 2022 | 92 | 39% | 8% | 0 | 690 | 10 ug/L EPA limit | |
| E. coli 1997 to 2022 | 229 | 5% | 5% | 0 | 52 | 0 MPN/100mL EPA limit | |
| Lead 1977 to 2022 | 93 | 58% | 4% | 0 | 400 | 15 ug/L EPA limit | |
| Uranium 1994 to 2024 | 476 | 49% | <1% | 0 | 44.2 | 30 ug/L EPA limit | |
| Radium (226 + 228) 1994 to 2022 | 444 | 67% | <1% | 0.079 | 7.5 | 5 pCi/L EPA limit | |
| Fluoride 1941 to 2022 | 96 | 70% | 0% | 0.1 | 1.8 | 4 mg/L EPA limit | |
| Copper 1983 to 2021 | 94 | 36% | 0% | 0 | 0.6 | 1.3 mg/L EPA limit | |
| PFOA 2021 to 2022 | 26 | 0% | 0% | 0 | 0 | 4 ng/L EPA limit | |
| PFOS 2021 to 2022 | 25 | 0% | 0% | 0 | 0 | 4 ng/L EPA limit | |
| Radon 1994 to 2014 | 372 | 99% | no limit | 640 | 18,600 | 2,000 pCi/L health guideline | |
| Manganese 1948 to 2022 | 97 | 96% | no limit | 32 | 5,620 | 300 ug/L health guideline | |
| Sodium 1949 to 2022 | 95 | 100% | no limit | 9.9 | 30,500 | 20 mg/L health guideline | |
| Chloride 1941 to 2021 | 90 | 100% | no limit | 10.8 | 880 | 250 mg/L nuisance level | |
| Iron 1947 to 2021 | 88 | 93% | no limit | 292 | 110,000 | 300 ug/L nuisance level |
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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
- Volatile organic compounds (VOCs)39,722 leaking underground storage tank sites on record locally.
- Iron29% of 65,654 local wells tested were above the North Carolina groundwater standard.
- Manganese24% of 110,182 local wells tested were above the North Carolina groundwater standard.
- E. coli5% of 229 local samples were above the limit.
- Copper<1% of 65,754 local wells tested were above the North Carolina groundwater standard.
- Radium (226 + 228)<1% of 444 local samples were above the limit.
- Nitrite<1% of 46,031 local wells tested were above the EPA limit.
- RadonMedian local reading is 640 pCi/L.
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
Common questions
Is there arsenic in well water in North Carolina?
Arsenic was detected in 39% of 92 public well samples in North Carolina, and 8% 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
- Alamance2% lead
- Alexander6% arsenic
- Alleghany7% lead
- Anson19% arsenic
- Ashe4% lead
- Avery5% lead
- Beaufort2% lead
- Bertie2% nitrate
- Bladen<1% lead
- Brunswick1% lead
- Buncombe2% lead
- Burke2% nitrate
- Cabarrus3% arsenic
- Caldwell2% arsenic
- Camden0% arsenic
- Carteret3% lead
- Caswell3% lead
- Catawba3% arsenic
- Chatham3% arsenic
- Cherokee3% lead
- Chowan2% lead
- Clay2% lead
- Cleveland3% lead
- Columbus<1% lead
- Craven3% lead
- Cumberland7% lead
- Currituck5% arsenic
- Dare5% lead
- Davidson5% arsenic
- Davie2% nitrate
- Duplin2% nitrate
- Durham2% lead
- Edgecombe4% nitrate
- Forsyth6% uranium
- Franklin3% lead
- Gaston3% arsenic
- Gates2% lead
- Graham2% lead
- Granville2% lead
- Greene5% lead
- Guilford4% lead
- Halifax1% lead
- Harnett5% lead
- Haywood2% lead
- Henderson5% lead
- Hertford3% nitrate
- Hoke13% lead
- Hyde1% lead
- Iredell1% lead
- Jackson3% lead
- Johnston3% lead
- Jones1% lead
- Lee4% arsenic
- Lenoir3% nitrate
- Lincoln4% arsenic
- Macon5% lead
- Madison6% lead
- Martin2% lead
- McDowell4% lead
- Mecklenburg3% lead
- Mitchell2% lead
- Montgomery8% arsenic
- Moore7% lead
- Nash3% lead
- New Hanover3% copper
- Northampton5% nitrate
- Onslow3% lead
- Orange3% lead
- Pamlico2% lead
- Pasquotank0% arsenic
- Pender<1% lead
- Perquimans2% arsenic
- Person3% lead
- Pitt<1% lead
- Polk4% lead
- Randolph5% arsenic
- Richmond9% nitrate
- Robeson5% nitrate
- Rockingham3% arsenic
- Rowan3% lead
- Rutherford2% lead
- Sampson7% nitrate
- Scotland6% lead
- Stanly18% arsenic
- Stokes3% lead
- Surry4% lead
- Swain2% lead
- Transylvania3% lead
- Union19% arsenic
- Vance3% lead
- Wake10% uranium
- Warren3% lead
- Washington2% lead
- Watauga4% lead
- Wayne5% lead
- Wilkes2% lead
- Wilson2% lead
- Yadkin2% nitrate
- Yancey3% lead
1 counties have fewer than 30 public samples and are included in the North Carolina totals above rather than shown separately: Tyrrell.
Sources
- USGS Water Quality Portal: 2,507 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.
- 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.