South Carolina well water by county: arsenic and nitrate
Modelled arsenic and nitrate for private-well users in every South Carolina county, what to test for, and where to find a certified lab. Private wells aren’t covered by the Safe Drinking Water Act.
All 46 counties
- Lexington CountyWell users 47,200Arsenic about 1 in 100Nitrate 1.3 mg/L
- Horry CountyWell users 45,400Arsenic about 2 in 100Nitrate 0.0 mg/L
- York CountyWell users 45,100Arsenic about 1 in 100Nitrate 0.4 mg/L
- Berkeley CountyWell users 43,700Arsenic about 1 in 100Nitrate 0.1 mg/L
- Florence CountyWell users 43,700Arsenic about 2 in 100Nitrate 0.2 mg/L
- Orangeburg CountyWell users 32,000Arsenic about 2 in 100Nitrate 0.3 mg/L
- Spartanburg CountyWell users 31,400Arsenic about 1 in 100Nitrate 1.2 mg/L
- Greenville CountyWell users 30,500Arsenic about 1 in 100Nitrate 1.2 mg/L
- Aiken CountyWell users 29,300Arsenic about 1 in 100Nitrate 1.1 mg/L
- Sumter CountyWell users 27,100Arsenic about 2 in 100Nitrate 0.5 mg/L
- Richland CountyWell users 26,600Arsenic about 1 in 100Nitrate 0.3 mg/L
- Charleston CountyWell users 26,600Arsenic about 2 in 100Nitrate 0.1 mg/L
- Williamsburg CountyWell users 23,700Arsenic about 1 in 100Nitrate 0.0 mg/L
- Colleton CountyWell users 23,500Arsenic about 1 in 100Nitrate 0.0 mg/L
- Darlington CountyWell users 21,900Arsenic about 4 in 100Nitrate 0.7 mg/L
- Clarendon CountyWell users 21,800Arsenic about 1 in 100Nitrate 0.1 mg/L
- Dorchester CountyWell users 21,100Arsenic about 1 in 100Nitrate 0.0 mg/L
- Laurens CountyWell users 20,100Arsenic about 1 in 100Nitrate 0.7 mg/L
- Anderson CountyWell users 19,800Arsenic about 1 in 100Nitrate 1.5 mg/L
- Chesterfield CountyWell users 18,300Arsenic about 2 in 100Nitrate 0.5 mg/L
- Chester CountyWell users 17,900Arsenic about 2 in 100Nitrate 0.2 mg/L
- Newberry CountyWell users 16,200Arsenic about 2 in 100Nitrate 0.4 mg/L
- Greenwood CountyWell users 15,500Arsenic about 1 in 100Nitrate 0.3 mg/L
- Lancaster CountyWell users 15,100Arsenic about 2 in 100Nitrate 0.2 mg/L
- Beaufort CountyWell users 14,400Arsenic about 3 in 100Nitrate 0.0 mg/L
- Saluda CountyWell users 13,800Arsenic about 1 in 100Nitrate 0.5 mg/L
- Jasper CountyWell users 12,900Arsenic about 2 in 100Nitrate 0.0 mg/L
- Cherokee CountyWell users 12,400Arsenic about 1 in 100Nitrate 0.9 mg/L
- Georgetown CountyWell users 12,000Arsenic about 1 in 100Nitrate 0.0 mg/L
- Abbeville CountyWell users 12,000Arsenic about 1 in 100Nitrate 0.2 mg/L
- Kershaw CountyWell users 12,000Arsenic about 2 in 100Nitrate 0.3 mg/L
- Calhoun CountyWell users 11,000Arsenic about 2 in 100Nitrate 0.7 mg/L
- Fairfield CountyWell users 10,800Arsenic about 1 in 100Nitrate 0.1 mg/L
- Barnwell CountyWell users 10,300Arsenic about 2 in 100Nitrate 0.4 mg/L
- Marion CountyWell users 10,300Arsenic about 2 in 100Nitrate 0.1 mg/L
- Marlboro CountyWell users 10,300Arsenic about 2 in 100Nitrate 1.9 mg/L
- Hampton CountyWell users 10,300Arsenic about 1 in 100Nitrate 0.0 mg/L
- Oconee CountyWell users 9,600Arsenic about 1 in 100Nitrate 0.3 mg/L
- Edgefield CountyWell users 9,500Arsenic about 1 in 100Nitrate 1.2 mg/L
- Dillon CountyWell users 9,400Arsenic about 1 in 100Nitrate 0.9 mg/L
- Lee CountyWell users 8,500Arsenic about 2 in 100Nitrate 0.5 mg/L
- Pickens CountyWell users 7,000Arsenic about 1 in 100Nitrate 0.4 mg/L
- Bamberg CountyWell users 6,400Arsenic about 2 in 100Nitrate 0.2 mg/L
- Allendale CountyWell users 4,200Arsenic about 2 in 100Nitrate 0.0 mg/L
- Union CountyWell users 3,900Arsenic about 1 in 100Nitrate 0.6 mg/L
- McCormick CountyWell users 3,100Arsenic about 1 in 100Nitrate 0.1 mg/L
Each mark = 1 in 100 well users the model places above 10 µg/L arsenic (scale 0–10)10 mg/L nitrate: the federal limit (MCL) for public systems
- These figures describe the area, not your well. Only a lab test shows what’s in your water.
- CDC says the Well Water Index figures “do not describe risk to individual wells.” (CDC Tracking Network)
- The arsenic model is better at spotting low-arsenic areas than at confirming high ones.
- Well-user counts are 2010 USGS estimates; tract values are averages over each census tract.
- Total coliform bacteriaEvery year
- NitrateEvery year
- Total dissolved solidsEvery year
- pHEvery year
- ArsenicAsk your local health department
EPA: Private Drinking Water Wells · CDC: Guidelines for Testing Well Water
Use a state-certified lab
South Carolina Department of Environmental Services lists the laboratories certified to test drinking water in South Carolina.
Screening tells you if something is worth a closer look
A lab result is the number you can act on.
As an Amazon Associate, PurityMap earns from qualifying purchases. Affiliate disclosure
Lab-certified results
ETR Labs Basic Water Quality Test Kit
ETR Laboratories
50+ substances, including lead, copper, arsenic, nitrate, hardness and coliform bacteria
- Analyzed by Environmental Testing and Research Laboratories (ETR Labs), Leominster, MA · ISO/IEC 17025:2017, ANAB certificate AT-2638
- Turnaround: 2–4 business days after the lab receives it
What it can't tell you: It does not test PFAS, and not every result on the panel falls under the lab's accredited scope.
Screening: quick check, not lab-grade
Watersafe Drinking Water Test Kit
Silver Lake Research
Lead, bacteria, nitrate, copper, iron, chlorine, hardness and pH
- Turnaround: Minutes; the bacteria test can take up to 48 hours
What it can't tell you: Each test gives a yes/no or a rough range, not a lab number, and it cannot detect PFAS or arsenic.
A mail-in kit’s lab is accredited (ISO/IEC 17025) but may not be certified by your state. For a home sale, a loan, or a health-department follow-up, use a state-certified lab.
South Carolina well water
Sources: CDC Well Water Index (2024) · USGS arsenic and nitrate models · USGS domestic well populations · EPA and CDC testing guidance. Data last updated 2026-10-08. All sources →
How many people use private wells in South Carolina?
About 877,400 people across 46 South Carolina counties, by the USGS 2010 estimate. USGS models place about 14,000 of them in areas where wells are likely to be above the 10 µg/L arsenic limit. These are area estimates, not well results.
Are private wells regulated in South Carolina?
The quality and safety of drinking water from private domestic wells are not regulated by the Federal Government under the Safe Drinking Water Act nor by most state governments and laws. (EPA) Testing and treatment are the owner's responsibility.
Where can I get my well tested in South Carolina?
South Carolina Department of Environmental Services keeps the list of laboratories certified to test drinking water in South Carolina. Only use laboratories that are certified to do drinking water testing. (EPA)