Well water testing in Union County, North Carolina

Last verified: 2026-10-30 · 20 sources · What we couldn't verify

Arsenic is the big issue for Union County wells: in UNC's analysis of state lab results, 19.46% of 5,154 wells tested were above the 10 µg/L arsenic standard. Union County Environmental Health offers well water testing, with a $70 bacteria test and a $130 inorganic panel that includes arsenic.

Union County Environmental Health says approximately 25 percent of the county's population relies on groundwater for drinking water. Statewide, NCDHHS says about 2.4 million North Carolinians rely on groundwater as their primary drinking water source, and that since 2008 every newly constructed drinking water well must be tested for bacterial and chemical contaminants within 30 days of completion. There are no other required tests for private wells.^[1][12]

Free and low-cost testing programs

Labs that serve the county

North Carolina certifies drinking-water labs for each contaminant, so check that a lab is certified for the specific test you need, especially arsenic. Among nearby commercial labs, only EMSL's Pineville lab lists arsenic. The state list also includes the Union County Health Department lab (2330 Concord Ave., Monroe, lab 37517), which is certified for coliform and E. coli. Well owners order county tests through Environmental Health, not the lab directly. Other commercial labs in Charlotte and Huntersville are on the state list, but we haven't confirmed that they take homeowner well samples.^[14][1]

Local contaminants of concern

• Major concern Arsenic. In the UNC Superfund Research Program's analysis of NCWELL data (state lab results), 1,003 of 5,154 Union County wells tested (19.46%) were above the 10 µg/L arsenic standard, with a maximum of 303 µg/L. In the state lab's 1998-2010 county report, 685 of 3,478 wells (19.70%) were above it. Union County says the arsenic comes from the Carolina Slate Belt's metamorphosed volcanic and sedimentary rocks, which underlie about two-thirds of the county. A 2009 NC Division of Water Quality study in northern Union County found 14 of 23 nearby private wells above 10 µg/L, all in the mudstone member of the Cid Formation. In UNC's 2023 free testing of 224 Union County wells, 18% of samples were above the standard (maximum 161 ppb). Arsenic has no taste, color or smell, so testing is the only way to know.^{[4][5][6][1][7][8]}
• Major concern Manganese and iron. 30.54% of 5,137 wells tested exceeded EPA's 300 µg/L manganese health advisory, and 20.57% of 2,353 exceeded the DEQ iron level of 2,500 µg/L (UNC/NCWELL). Union County suggests considering treatment or bottled water above 0.3 mg/L manganese and says water for pregnant women and young children should be below the standard. Iron and manganese also affect which arsenic treatment will work.^[4][1]
• Moderate concern Lead and copper (from plumbing). 99 of 5,140 wells tested (1.93%) were above the 15 µg/L lead action level, with a maximum of 1,740 µg/L, and 0.55% of 2,354 were above the copper action level (UNC/NCWELL). In UNC's 2023 study, 9% of samples were above the lead standard. Slides from UNC and Union County's 2023 community meeting say lead isn't typically found in Union County groundwater and comes from plumbing fixtures.^[4][8]
• Moderate concern Sodium. Every one of the 2,242 Union County wells tested for sodium (100%) was above EPA's 20,000 µg/L sodium advisory level, which matters for people on low-sodium diets (UNC/NCWELL).^[4]
• Lower concern Nitrate / nitrite. 21 of 1,550 wells tested (1.35%) exceeded the 10,000 µg/L (10 mg/L) nitrate standard (UNC/NCWELL). Union County advises nitrate testing for any well used by infants and young children.^[4][1]
• Not verified Uranium and radon. The UNC/NCWELL summary has only one Union County uranium result, and we found no Union County radon-in-water data. Unverified.^[4]
• Not verified Bacteria. We found no countywide bacteria rate. Slides from UNC and Union County's 2023 community meeting list coliform bacteria and E. coli among common contaminants in Union County well water, and the county recommends a coliform test every year.^[8][1]
• Not verified PFAS. We found no Union County private-well PFAS data in the sources reviewed, and PFAS isn't on the county's test list. Unverified.^[1]

A county rate can't tell you what's in your well. Only a test can. See what to test for.

Typical cost

Prices are from the published lists cited, as of the last-verified date. Confirm before ordering.

How often to test

• Every year: total and fecal coliform bacteria.^[1][11]
• Every two to three years: heavy metals (including arsenic), nitrate, nitrite, lead and copper.^[1]
• Every five years: pesticides and VOCs. Test yearly if you know a particular pesticide is used in your area.^[1]
• New wells must be tested within 30 days of completion. Test again after well repairs, flooding, or any change in taste, color or odor.^[11][12]

How to collect a sample

If you use Union County Environmental Health, start with a Water Sample Request Form and ask the office how and where your sample will be collected. If you collect your own sample for a private lab, follow that lab's instructions. These steps come from K & W Laboratories' FAQ:

1. Bacteria: use the lab's sterile bottle and don't rinse it (the white powder inside is a dechlorinating agent). Remove the aerator, flame the tap or wipe it with bleach, run cold water for five minutes, then fill to the 100 mL line without touching the inside of the bottle or cap. Never sample from a hose.
2. Nitrate/nitrite: run the tap until the water temperature stabilizes, fill the lab's bottle, and keep it on ice. Don't flame or bleach the tap for this sample.
3. Lead: collect after the water has sat in the pipes at least 6 hours without use, filling the bottle completely from the cold tap.
4. Arsenic: collect at the well in the lab's acid-preserved bottle and fill to the neck. Without a preserved bottle, get the sample to the lab quickly.
5. Bacteria samples must be back at the lab within 30 hours of collection.

Source^[1][3][16]. General steps: How to test your well water.

After you get results

Union County recommends a full inorganic panel before choosing arsenic treatment, because iron and manganese affect which system will work. Its options include whole-house (point-of-entry) or single-tap (point-of-use) treatment, and an NSF-certified pitcher filter rated for arsenic as a low-cost stopgap. Treatment options presented at UNC's 2023 Union County meeting were iron-oxide adsorptive media, activated alumina, anion exchange or reverse osmosis for arsenic; oxidizing filtration or a softener for iron and manganese; and chlorination, ozone or UV for bacteria. Questions: Union County Environmental Health, 704-283-3553.^[1][8]

What we couldn't verify

• How Union County collects samples (staff visit or self-collection), where to pick up bottles, and turnaround times. The Water Sample Request Form is a script-only page we couldn't read.
• Whether K & W Laboratories accepts mailed samples, and its prices.
• Whether EMSL's Pineville lab accepts walk-in homeowner samples, which EMSL lab analyzes its mail-in kits, and whether the Advanced kit includes arsenic.
• Whether Chem-Bac Laboratories takes homeowner well samples, and its prices.
• Whether other state-certified commercial labs in Charlotte and Huntersville (Eurofins Charlotte, Pace Huntersville) accept homeowner samples.
• Any currently open free or subsidized well testing program in Union County (the 2023 UNC testing and ARPA well repair programs are closed).
• Uranium, radon-in-water and PFAS occurrence in Union County private wells.
• A countywide bacteria rate for private wells.
• The date range of the NCWELL data behind the UNC fact sheet (not stated on the fact sheet).

Sources

1. Union County, NC (Environmental Health): Wells and Water Testing
2. Union County, NC: Environmental Health Fees
3. Union County, NC: Well and Water Testing: Applications and Forms (Water Sample Request Form)
4. UNC Superfund Research Program: Well Water Contaminants in Union County (fact sheet, 2022; NCWELL database, Eaves et al. 2022)
5. NCDHHS Division of Public Health: Union County well water contaminant report (State Lab private well samples, PDF)
6. NCDHHS Division of Public Health: Well Water & Health: Contaminant Maps by County (State Lab samples 1998-2010)
7. NC Division of Water Quality (NCDEQ): A hydrogeological assessment of arsenic in the Carolina terrane of Union County, North Carolina (Groundwater Circular 2009-01)
8. UNC Superfund Research Program and Union County Environmental Health: Private Well Testing Results in Union County, NC (community meeting slides, May 24, 2023)
9. Union County, NC: Free Well Water Tests to Private Well Users in Union County (news, Feb. 23, 2023)
10. Union County, NC: Private Drinking Water Well Rehabilitation and Repair Program
11. NCDHHS Division of Public Health: Private Wells: Frequently Asked Questions about Testing
12. NCDHHS Division of Public Health: Private Wells: Facts and Figures
13. N.C. State Laboratory of Public Health: Environmental Inorganic Chemistry (private water system samples)
14. N.C. State Laboratory of Public Health: Certified Drinking Water Laboratories (commercial and health department lists, lab detail pages) (search form; choose "View a list of all laboratories", then click a lab name for its details)
15. K & W Laboratories, LLC: K&W Laboratories (home page)
16. K & W Laboratories, LLC: FAQ: How do I collect a sample
17. EMSL Analytical, Inc.: Charlotte, North Carolina Testing Laboratory (LAB 41)
18. EMSL Analytical, Inc.: Product Catalog: Water Test Kits
19. EMSL Test Kits: Drinking Water Test Kit
20. Chem-Bac Laboratories, Inc.: Drinking Water (microbiological testing)

All sources accessed on or before 2026-10-30.

More useful links

• NC State Laboratory of Public Health - certified laboratory search (NC state site; it sometimes fails to connect, so try again if it does)
• Union County Water Sample Request Form (online)

Other North Carolina counties

• Wake County

All North Carolina county guides