Indiana Private Well Water Quality 2026

PFAS Contamination Across Indiana’s Groundwater

Indiana’s PFAS problem is both widespread and underreported. When Indiana’s Attorney General filed suit against 22 PFAS manufacturers in April 2024, he pointed to IDEM sampling data showing PFAS in public drinking water above federal health advisory levels across 24 Indiana counties. For private well owners — whose water is tested by no-one except themselves — the actual extent of contamination is far harder to quantify.

The contamination has several distinct sources. Military bases across the state used AFFF firefighting foam for decades, with PFAS migrating into surrounding groundwater. Industrial operations — including manufacturing facilities tied to the automotive and electronics sectors — have discharged PFAS into waterways and soils. And PFAS-containing biosolids, applied to agricultural land as fertiliser, have created a diffuse contamination pathway across farming communities throughout the state.

Despite this picture, Indiana has taken no legislative action to establish its own PFAS drinking water limits. In 2025, bills including HB1286 and HB1366 — which would have established PFAS water safety standards and required PFAS biosolids testing respectively — both failed to advance in the Indiana General Assembly. The state has instead passed Senate Bill 426, which protects water utilities from PFAS lawsuits. Private well owners are left to navigate the contamination without a state safety net.

The federal MCLs for PFOA and PFOS (4 ppt each), finalised by the EPA in April 2024, apply only to public water systems. Private wells in Indiana have no equivalent legal protection — testing and treatment remain entirely the homeowner’s responsibility.

Military Bases and Known Contamination Sites

Indiana has several military installations with documented PFAS contamination in groundwater. Grissom Air Reserve Base near Kokomo — a former active-duty Air Force installation converted to reserve use in 1994 — saw PFAS detected in 16 of 18 on-base monitoring wells not used for drinking water, though on-base drinking water wells met the standards in place at the time of testing. As federal MCLs have tightened significantly since, the picture near the base warrants close attention for private well owners in the surrounding area.

At Camp Atterbury — spanning parts of Bartholomew, Brown and Johnson counties near Edinburgh — contractors confirmed PFAS in groundwater near a former firefighting foam storage site. The Indiana National Guard has committed to continued investigation. The Shelbyville Army Aviation Support Facility and Fort Benjamin Harrison have also been identified as contaminated sites, with PFAS detected in soil, sediment, surface water and groundwater near fire training areas, fire stations and hangars.

In northeast Indiana, Treaty Creek became the focus of an IDEM investigation after PFAS — including PFOS and PFOA — were detected in the waterway. Of private wells tested within 300 feet of the creek, five showed detectable PFAS levels, with three exceeding the EPA’s then-current health advisory of 70 ppt. After the 2024 EPA rule revision setting the limit for PFOA and PFOS at 4 ppt each, IDEM reevaluated its data and found three previously collected samples now exceeded the new PFOS limit. Treatment systems were installed at the affected properties. This case is a clear illustration that contamination in Indiana’s private wells is not confined to the immediate vicinity of military sites.

Nitrate Contamination: A Real Risk in Agricultural Indiana

Indiana is one of the most agriculturally intensive states in the country, and nitrate contamination from fertiliser and livestock waste is a documented risk for private well owners — particularly those with shallow wells near farmland. Studies by the USGS and the Indiana Farm Bureau found nitrate concentrations exceeding the 10 mg/L drinking water standard in 3.5% to 4.5% of private wells statewide. The risk is significantly higher for shallow wells: nearly 12% of wells under 50 feet deep exceeded the standard, compared to under 1% of wells deeper than 100 feet.

High nitrate levels are particularly dangerous for infants under six months, and can cause methemoglobinemia — a potentially fatal condition that impairs blood oxygen transport. Beyond agriculture, septic systems and livestock operations can also be sources of nitrate. IDEM requires manure storage to be located at least 100 feet from wells, but older farms and legacy systems may not meet current standards.

Arsenic and Bacteria

Arsenic is a naturally occurring concern in Indiana well water. In parts of the state — particularly where wells draw from shale bedrock — arsenic can be elevated above the 10 ppb EPA standard. Marion County Public Health identifies arsenic as a specific well water risk in its jurisdiction, noting that treatment systems including reverse osmosis are necessary to address it. Like PFAS, arsenic is colourless and tasteless and cannot be identified without laboratory testing.

Coliform bacteria contamination is a risk for any private well, particularly those with ageing or poorly sealed casings, wells located near septic systems, and properties that have experienced flooding. Indiana’s septic system rules require new systems to be set at least 50 feet from domestic wells, but older properties with legacy infrastructure may not meet that standard.

Regulatory Position for Indiana Well Owners

Private wells in Indiana are not regulated by either the EPA’s Safe Drinking Water Act or Indiana state law. Neither IDEM nor the Indiana Department of Health (IDOH) has authority to mandate testing of private wells or to set enforceable water quality standards for private drinking water. The IDOH recommends annual testing as a minimum and certifies laboratories that analyse well water samples, but compliance is entirely voluntary.

IDEM does run a Groundwater Monitoring Network (GWMN), which since 2008 has collected samples from over 1,200 private residential drinking water wells across the state. This voluntary programme provides residents with free testing and adds to the scientific picture of Indiana groundwater quality — but it reaches only a fraction of the state’s private well owners.

Check our Indiana municipal water quality page for city-by-city tap water data including Indianapolis, or use our live boil water notice tracker for active advisories across the state.

Known High-Risk Areas in Indiana

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

How to Test Your Indiana Well Water — and What to Do Next

The IDOH recommends that all Indiana private well owners test their water at minimum once a year. Given that PFAS has been detected above federal health advisory levels across 24 Indiana counties, a PFAS-specific test is strongly advisable at least once — and should be treated as urgent if you live near any military installation, industrial site, or an area where PFAS-containing biosolids have been applied to farmland.

To arrange testing, contact your local county health department or use the IDOH certified laboratory list at in.gov/health. The IDOH laboratory also accepts drinking water samples directly for bacteria, nitrate, and sodium analysis. For PFAS testing, you will need a certified private laboratory — IDEM’s Groundwater Section (800-451-6027) can advise. If you believe your well may be contaminated from a man-made source nearby, you can file a complaint with IDEM and request investigation.

For filter options, our well water filter guide covers reverse osmosis systems for PFAS, arsenic and nitrate, UV disinfection for bacteria, and whole-house well systems for comprehensive treatment. You can also browse our full water filter solutions page or check your ZIP code for local water quality context.

For other Midwest well water risks, see our pages on Michigan wells, Wisconsin wells, Iowa wells, and Ohio wells. Return to the private well water directory to find your state.