North Carolina Well Water Tests
Roughly one North Carolinian in four, 2,407,661 people or 24.0% of the state, drank from a household well in 2015, according to USGS water-use estimates. Few states lean on private wells as heavily, and almost none of those wells is regulated once the water is flowing.
Each county environmental health office sells water tests run by the State Laboratory of Public Health, and prices vary a lot. County fee lists put a basic bacteria test at $25 in Wake County and $70 in Union County, and an inorganic panel at $50 and $130 in the same two counties. The problems also differ by geology: uranium and radon on the Wake granites, arsenic in the Union slate belt, iron and low pH on the Johnston Coastal Plain.
Permits
Step 1: Find your county office. Statewide, NC G.S. 87-97 makes the local health department responsible for permitting, inspecting and testing new private wells; for an existing well, testing is voluntary and is ordered through the same Environmental Health office.
Step 2: Ask for a bacteria test and a full inorganic panel first. Wake County bundles that pairing into its First Timer's Package; on the Wake, Johnston and Union County fee lists, bacteria tests run $25 to $70 and inorganic panels $50 to $130.
Step 3: Add targeted tests where geology calls for them: arsenic speciation in the Carolina slate belt, a radionuclide package on the Rolesville granite, iron or sulfur bacteria where staining and odor show up.
Step 4: Keep your well's siting in mind when you change anything near it; 15A NCAC 02C .0107 sets well setbacks, including 50 feet from a septic tank and drainfield for a single-family well.
Step 5: Choose treatment from the numbers, then retest through the county once it is installed.
Local conditions
The Piedmont's crystalline rock and the Coastal Plain's sediments give very different water. NC DHHS publishes county averages from State Laboratory results, and UNC's Superfund Research Program has turned the 1998-2019 records into county tables; both are linked on each county page.
Granite in the north-central Piedmont carries uranium and radon. The NC Radon-in-Water Advisory Committee report maps 19 counties with areas particularly susceptible to radon in well water, centered on the Rolesville and related granites near Raleigh.
Slate-belt rock in the southern Piedmont, from Union County north through the Carolina terrane, is where arsenic results cluster, according to NC DWQ work in Union County.
East of the fall line, Coastal Plain aquifers tend to give soft but iron-rich and often acidic water, the classic case for a neutralizer and iron filter.
What drives local prices
- Testing is the smallest line: the Wake County fee list starts at $20 for a single metal, and the Union County fee page tops out at $130 for its inorganic panel.
- Equipment depends on the result. HomeGuide's published installed ranges are $1,000-$3,500 for an iron filter, $800-$2,500 for a neutralizer, $1,000-$4,000 for arsenic treatment and $300-$950 for under-sink reverse osmosis.
- County-to-county differences in contamination, not labor, are the biggest local price driver; a Union arsenic system and a Johnston iron train are different purchases.
- Retesting after installation adds one more county lab fee each year.
Common jobs
- Arsenic media or reverse osmosis in the southern Piedmont
- Uranium and radon treatment on the Raleigh-area granites
- Neutralizer and iron filter trains on the Coastal Plain
- Manganese filtration statewide
- County lab retesting after installation
Service area
This hub links our North Carolina county pages: Wake (Raleigh, Wake Forest, Fuquay-Varina) and Johnston (Smithfield, Clayton, Benson).
Each county page lists the Environmental Health office, its test prices and the State Laboratory results for that county.
Communities: Wake County, Johnston County, Raleigh, Smithfield, Clayton
If it is an emergency
If a bacteria result comes back positive anywhere in the state, stop drinking the water, disinfect the well and retest through your county Environmental Health office before choosing equipment.
Questions about North Carolina
Does North Carolina require testing of an existing private well?
No. G.S. 87-97 requires testing when a new well is built. After that, testing is up to the owner, which is why the county programs exist.
Who runs the lab tests?
The State Laboratory of Public Health analyzes samples sent in by county Environmental Health offices; certified private labs are another option.
Which North Carolina counties have the most private wells?
USGS's 2015 estimates put Mecklenburg and Wake at the top by headcount; Wake is the largest on this site.
What should a first test include?
A bacteria test and a full inorganic panel, then arsenic, uranium or radon depending on where you live.
Why do results vary so much by county?
Geology. Granite, slate-belt rock and Coastal Plain sediments each release different metals into groundwater.
Sources
- USGS: Estimated Use of Water in the United States, county-level data for 2015 (Dieter et al. 2018)
- NC G.S. 87-97: Private drinking water well permits, inspection and testing
- 15A NCAC 02C .0107: Well location and construction standards
- NC DHHS: Well water and health, private well results by county
- UNC Superfund Research Program: Well water contaminants by county
- NC Radon-in-Water Advisory Committee: Final Report (March 2011)
- NC DWQ: Hydrogeological assessment of arsenic in the Carolina terrane of Union County
- Wake County: Available well water tests and fees
- Johnston County Environmental Health: Fee schedule (effective July 1, 2026)
- Union County Environmental Health: Fees
- EPA: National Primary Drinking Water Regulations
- HomeGuide: well water filtration, water softener and reverse osmosis cost guides (2025-2026; cited as text)
County pages in North Carolina
Related
Fees and rules change; confirm with the county office before you order. Compare installed prices in the treatment system cost guide, or run the treatment selector with your lab results.