Arsenic in North Carolina well water
In North Carolina, 2% of 110,383 private wells tested between 1998 and 2019 had arsenic above the North Carolina groundwater standard (10 ug/L), according to the NC State Laboratory of Public Health (NCWELL).
Arsenic occurs naturally in New England bedrock and dissolves into well water. Long-term exposure raises the risk of bladder, lung and skin cancers, and is linked to heart disease and lower IQ in children. It has no taste or smell, so testing is the only way to know.
Check your arsenic number
Type the value from your lab report. It is compared to the North Carolina groundwater standard and the EPA limit, the same way the full interpretation does it.
Getting it fixed
Book a free in-home water test with a licensed local company, or see the treatment guide for what removes arsenic.
By county, from homeowner tests
Share of private wells above the state guidance level (10 ug/L) in tests homeowners sent to the state lab, 1998 to 2019.
| County | Wells tested | Above state level | Highest | |
|---|---|---|---|---|
| Union | 5,154 | 19% | 303 ug/L | |
| Anson | 132 | 19% | 154 ug/L | |
| Stanly | 1,278 | 18% | 806 ug/L | |
| Montgomery | 576 | 8% | 133 ug/L | |
| Alexander | 272 | 6% | 175 ug/L | |
| Randolph | 2,619 | 5% | 106 ug/L | |
| Currituck | 1,130 | 5% | 130 ug/L | |
| Davidson | 697 | 5% | 100 ug/L | |
| Lincoln | 2,333 | 4% | 390 ug/L | |
| Lee | 278 | 4% | 29 ug/L | |
| Moore | 1,280 | 3% | 167 ug/L | |
| Cabarrus | 1,382 | 3% | 247 ug/L | |
| Cumberland | 2,044 | 3% | 161 ug/L | |
| Richmond | 524 | 3% | 101 ug/L | |
| Catawba | 1,567 | 3% | 388 ug/L |
By county, from individual samples
Public monitoring samples against the EPA limit (10 ug/L); counties with at least 30 samples.
| County | Samples | Detected | Above EPA limit | Median | Highest |
|---|---|---|---|---|---|
| Mecklenburg | 59 | 37% | 8% | 0 | 690 ug/L |
Sources
- NCWELL private well summaries: 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.
- Individual samples from the USGS Water Quality Portal and state monitoring, summarized per geography. arsenic counts and shares are listed on each county and town page with their sources.