Arsenic in Drinking Water in North Carolina
What residents of North Carolina need to know about arsenic in drinking water — including natural geological sources, private well risk, which utilities have documented violations, and how to remove arsenic from tap water.
Source: EPA SDWIS, NC Division of Water Resources, USGS · Last reviewed: 2025-01-01
Quick Answer
Is arsenic in drinking water a concern in North Carolina?
Yes. North Carolina has documented arsenic in private well water from Piedmont crystalline bedrock geology. The NC Piedmont — which spans most of the state's middle geographic tier from the Virginia border south to the South Carolina border — contains arsenic-bearing granite, gneiss, and schist formations. Studies have found elevated arsenic in private wells across many Piedmont counties.
Where does arsenic come from in North Carolina's water?
Crystalline Piedmont bedrock is the primary arsenic source in North Carolina. Private wells drilled into granite, gneiss, and other metamorphic rocks in the NC Piedmont are the main exposure pathway. The North Carolina Piedmont covers a broad swath of the state including the Charlotte, Triad (Greensboro/Winston-Salem/High Point), and Triangle (Raleigh/Durham/Chapel Hill) metro areas' outer suburban and rural zones.
What should North Carolina residents know?
North Carolina private well owners in Piedmont counties should test for arsenic. NC DEQ recommends testing at every real estate transfer for well properties. Approximately 40% of North Carolina residents use private wells — one of the highest rates in the Southeast. Reverse osmosis or NSF-certified activated alumina is required for treatment. Standard pitcher filters do not remove arsenic.
Key Facts
| EPA MCL | 10 µg/L (10 ppb) |
| MCLG | Zero |
| Primary source | NC Piedmont crystalline bedrock (granite, gneiss, schist) — widespread naturally occurring arsenic |
| Private well rate | ~40% of NC residents on private wells — one of highest rates in Southeast |
| State regulator | NC Division of Water Resources |
| Health effects | Bladder, lung, skin cancer; cardiovascular; diabetes risk |
| Effective treatment | Reverse osmosis (NSF/ANSI 58) or activated alumina |
Why Arsenic Matters in North Carolina
North Carolina's Piedmont extends across the middle third of the state and encompasses the densely populated Charlotte, Triad, and Triangle metropolitan areas' suburban and rural fringes. As these metros have expanded, more residents on the urban fringe rely on private wells in Piedmont bedrock — increasing the population at risk. NC DEQ has documented arsenic as a priority contaminant in NC private well surveys. The state's 40% private well rate — more than twice the national average — means millions of North Carolinians may face arsenic exposure without knowing it.
North Carolina Arsenic Program
North Carolina DEQ monitors arsenic under federal SDWIS and has documented arsenic in private wells in the Piedmont crystalline rock region. The NC Piedmont — including the Charlotte, Greensboro, and Raleigh metro areas — has documented arsenic in private wells drawing from fractured crystalline rock. NC's Division of Public Health provides guidance for private well testing and recommends arsenic testing statewide.
North Carolina Utilities With Arsenic Violation Records
The utilities listed below have at least one arsenic violation on record in EPA's SDWIS database. Violations may be open or resolved — see individual utility pages for current status and risk level.
How Does Arsenic Get Into Drinking Water?
Arsenic in drinking water is almost always naturally occurring — it leaches from arsenic-bearing rocks and minerals into groundwater over time. New England granite, Southwest volcanic geology, and Upper Midwest glacial aquifers are the primary high-risk formations. It has no taste, odor, or color.
Full arsenic overview — geology maps, health effects, all 50 statesWho Should Pay Closest Attention
Private well owners throughout the NC Piedmont face arsenic risk. Cabarrus, Stanly, Union, Anson, Richmond, Montgomery, Randolph, Davidson, Rowan, Iredell, and surrounding Piedmont counties have documented arsenic in private well surveys. NC's Mountain region counties also have arsenic from Blue Ridge crystalline geology.
Private well owners near mining districts or agricultural areas
Residents in states with documented volcanic or geothermal geology
Long-term consumers of water from small groundwater systems
Households in homes built before 1960 with older well casings
Residents whose well water has never been tested for arsenic
Anyone living in a state where bedrock wells are common
How to Check Your Situation in North Carolina
- 1
Identify your water source. If you use a public utility, use the ZIP lookup on this page to find your system and check its compliance record.
- 2
If on public water, review your utility's most recent Consumer Confidence Report (CCR) for arsenic monitoring data. The MCL is 10 ppb — your report should show recent test results.
- 3
If on a private well, order an arsenic test from a NC Division of Water Resources-certified laboratory. A basic arsenic test costs $15–$40. The state agency website maintains a certified lab list.
- 4
Test your well at the tap — not just at the wellhead. The entire water distribution system within your home can affect water quality.
- 5
If your test shows arsenic above 5 ppb, install certified treatment immediately. If above 10 ppb, do not use the water for drinking or cooking until treatment is installed.
- 6
Retest after installing treatment to confirm it is working as certified. Replace filter media on the manufacturer's schedule — an exhausted filter may not perform as rated.
Treatment Options for Arsenic
Boiling does not remove arsenic — it concentrates it. Standard activated carbon filters (Brita, etc.) do not effectively remove arsenic. Certified treatment is required.
NSF/ANSI Standard 58 — Reverse Osmosis
RO systems certified to NSF/ANSI 58 remove 85–95% of arsenic. Under-sink installation. Most effective for removing multiple contaminants simultaneously. Replace membranes and pre-filters on schedule.
Activated Alumina Filters
Activated alumina is specifically designed for arsenic and fluoride removal. Point-of-use or whole-house options available. Must be certified by NSF International or WQA for arsenic reduction. Requires periodic media regeneration or replacement.
Iron/Manganese Oxidation Filters
Effective for arsenic in iron-rich well water, which is common in the Midwest and New England. Oxidation converts dissolved iron and arsenic to a form that can be filtered out. Best when arsenic is co-occurring with high iron levels.
What does NOT work for arsenic
Standard activated carbon filters (Brita, refrigerator filters, most pitcher filters) do NOT effectively remove arsenic. Boiling concentrates arsenic. Water softeners do not remove arsenic. Only use products with NSF certification specifically for arsenic reduction.
Take Action Now
If you use a private well in North Carolina, test for arsenic — especially if you are in a region with granite, volcanic, or sedimentary geology. A basic arsenic test costs $15–$40 at a state-certified lab.
Public water users: check your utility's Consumer Confidence Report (CCR) for arsenic results. The EPA MCL is 10 ppb — any detection warrants attention.
If arsenic is detected above 10 ppb (or even below it, given MCLG is zero), install an NSF/ANSI 58-certified reverse osmosis system for drinking and cooking water.
Standard carbon filters do NOT remove arsenic — do not rely on a Brita or refrigerator filter for arsenic protection.
Frequently Asked Questions
Related Pages
Arsenic — National Overview
All U.S. utilities with arsenic records
North Carolina State Overview
All utilities and water quality data
North Carolina Well Water Guide
Testing, risks & certified labs for private wells
Reverse Osmosis Guide
Removes 85–95% of arsenic
Best Arsenic Filter Guide
What actually works (carbon doesn't)
PFAS in Drinking Water
The 'forever chemical' contamination overview
All Contaminants
Complete reference library
Data Sources & Provenance
All data on this page is sourced from official U.S. government or public datasets.
Find Your Utility
State Regulator
NC Division of Water Resources ↗