Arkansas Private Well Water Quality 2026

PFAS Contamination in Arkansas Well Water

Arkansas has documented PFAS contamination at multiple military installations, with groundwater plumes that extend well beyond base perimeters and into the surrounding residential areas where private wells are in use. The state has no mandatory PFAS testing requirements for private wells, and until 2025 had conducted no systematic statewide survey of PFAS in surface or groundwater. That changed when the Arkansas Natural Resources Commission approved $1.8 million in grant funding to begin testing surface waters — the first known statewide effort to catalogue PFAS contamination. The programme is in its early stages, and no data on private well contamination has yet been published at the statewide level.

The military base contamination picture in Arkansas is stark. At Little Rock Air Force Base in Jacksonville, PFOS and PFOA levels in groundwater reached a documented maximum of 390,000 parts per trillion — nearly 98,000 times the current federal safe limit of 4 ppt for PFOA and PFOS. According to the Environmental Working Group, Little Rock AFB holds the highest recorded groundwater PFAS detection of any Department of Defense installation in the country. The base opened in 1955 and used aqueous film-forming foam (AFFF) containing PFAS for firefighting and training for decades. Contamination from the base has migrated beyond the installation boundary, raising serious concerns for private well owners in the Jacksonville and Cabot areas of Pulaski and Lonoke Counties.

Eaker Air Force Base in Blytheville (Mississippi County) is a second Arkansas military site with documented PFAS contamination from legacy AFFF use. The base was closed in 1991 but environmental remediation has been ongoing, and contamination remains in the subsurface. The surrounding area — which retains some residential population — should be treated as a priority testing zone for private well owners.

A third confirmed site is the Arkansas Air National Guard Base at Fort Smith Municipal Airport (Sebastian County). Environmental investigation found PFAS contamination extending off-base, and interim measures — including the distribution of bottled water to affected residents — were put in place. Private well owners in residential areas near Fort Smith Municipal Airport should treat PFAS testing as a priority.

Arkansas has implemented legislation through Act 315 of 2021 restricting the use of PFAS-containing firefighting foam going forward. The state has also filed legal action against PFAS manufacturers. However, neither of these measures protects private well owners from contamination already in the ground. The Arkansas Division of Environmental Quality (DEQ) has stated it does not have state-required testing for PFAS in drinking water — and that applies to private wells in particular.

Arsenic in Arkansas Well Water

Arsenic occurs naturally in Arkansas groundwater due to the state’s geology. The Gulf Coastal Plain of eastern and southern Arkansas and the Ouachita Mountains of west-central Arkansas are the two regions where elevated arsenic concentrations have been documented in USGS and Arkansas DEQ sampling data. USGS studies have found arsenic in alluvial well water samples exceeding the 10 µg/L federal MCL in multiple locations within the Gulf Coastal Plain, particularly in the Bayou Bartholomew watershed area.

In the Ozark Plateaus region of northern Arkansas, groundwater travels through carbonate rock formations that can allow surface contaminants to reach wells quickly and with minimal filtration. The shallow, fractured bedrock wells common in this area are also susceptible to bacteria and nitrate infiltration. Arsenic concentrations in the Ouachita Mountains region are more variable and, in some studies, lower than might be expected given the mineralisation in fault zones — but the data coverage is limited, and the Arkansas Geological Commission recommends testing for households relying on wells in these formations.

Nitrate, Bacteria, and Agricultural Risk

Arkansas is the largest rice-producing state in the US and a major producer of poultry and soybeans. This intensive agricultural activity creates significant nitrate runoff risk, particularly in the flat Mississippi River Alluvial Plain of eastern Arkansas. Shallow wells in this region are highly vulnerable to nitrate infiltration from fertiliser application and poultry waste disposal. Elevated nitrate levels are dangerous for infants under six months — concentrations above 10 mg/L can cause methemoglobinemia (blue baby syndrome).

Poultry waste in particular is a documented concern in the Arkansas River Valley and northwest Arkansas, where large-scale poultry operations have historically contributed to both nitrate and bacteria contamination of nearby water sources. The Arkansas River Valley and Ozarks regions also face risk from carbonate geology: limestone aquifers allow water to travel rapidly through sinkholes and cave systems, meaning contaminants from the surface can reach wells without the filtration benefit of passing through soil layers.

Bacteria contamination from coliform organisms is a significant risk for older wells, wells that have been flooded (Arkansas is prone to significant flooding events), and wells located near septic systems. The Arkansas Department of Health administers approximately 400,000 onsite wastewater systems statewide — the proximity and condition of these systems relative to private wells is a key risk factor.

The Regulatory Gap for Arkansas Well Owners

Private wells in Arkansas fall outside both the federal Safe Drinking Water Act and Arkansas state drinking water regulations. The Arkansas Department of Health (ADH) has authority over public water systems, but private residential wells are entirely the responsibility of individual homeowners. There is no mandatory testing, no inspection requirement, and no notification system if contamination is found near a private well.

The Arkansas Water Well Construction Commission (AWWCC) regulates well construction and pump installation, ensuring new wells are built to minimum standards — but once a well is operational, ongoing water quality is the owner’s concern alone. The state has no PFAS MCLs of its own; well owners are not covered by the federal 4 ppt limits for PFOA and PFOS, which apply only to public water systems. Public systems must comply by the extended federal deadline of 2031.

See our Arkansas municipal water quality page for city-by-city tap water data including Little Rock, or use our live boil water notice tracker for active advisories across the state.

Known High-Risk Areas in Arkansas

If you live near any of the following locations, well water testing is urgent — not precautionary.