Nitrite in North Carolina well water
In North Carolina, <1% of 46,031 private wells tested between 1998 and 2019 had nitrite above the EPA limit (1 mg/L), according to the NC State Laboratory of Public Health (NCWELL).
Nitrite is the short-lived form of nitrogen from septic systems and fertilizer. It causes the same infant blood disorder as nitrate at a tenth of the concentration, and usually points to fresh contamination.
Check your nitrite number
Type the value from your lab report. It is compared to the EPA limit 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 nitrite.
By county, from homeowner tests
Share of private wells above the state guidance level (1 mg/L) in tests homeowners sent to the state lab, 1998 to 2019.
| County | Wells tested | Above state level | Highest | |
|---|---|---|---|---|
| Wake | 122 | <1% | 1.2 mg/L | |
| Haywood | 676 | <1% | 1.5 mg/L | |
| Wilson | 346 | <1% | 1 mg/L | |
| Durham | 352 | <1% | 1 mg/L | |
| Moore | 474 | <1% | 1.1 mg/L | |
| Currituck | 1,014 | <1% | 1 mg/L | |
| Wilkes | 502 | <1% | 1.6 mg/L | |
| Sampson | 602 | <1% | 1 mg/L | |
| Lincoln | 1,276 | <1% | 1 mg/L | |
| Nash | 1,239 | <1% | 2.1 mg/L | |
| Granville | 635 | <1% | 1 mg/L | |
| McDowell | 980 | <1% | 1 mg/L | |
| Cumberland | 1,165 | <1% | 1 mg/L | |
| Union | 1,550 | <1% | 1 mg/L | |
| Buncombe | 2,530 | <1% | 1 mg/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.