State Well Water Guide
Indiana Private Well Water Guide
About 30% of Hoosiers — approximately 2 million people — rely on private wells, with the highest rates in rural agricultural counties, the southern Indiana hill country, and exurban communities. Indiana's primary groundwater concerns mirror its land use: nitrate contamination from intensive corn and soybean farming, bacterial contamination from livestock operations and failing septic systems, and naturally elevated arsenic in specific glacial deposits. PFAS from military facilities and IDEM-regulated industrial sites are additional concerns. IDEM and the State Department of Health jointly oversee well standards.
Testing Guidance
Indiana recommends annual testing for coliform bacteria and nitrates for all private wells. Northern Indiana agricultural county well owners should prioritize nitrate and bacteria testing. Shallow glacial drift well owners in specific counties (Carroll, Cass, Miami, Wabash) should test for arsenic. Wells near Grissom ARB should be tested for PFAS.
What to Test For in Indiana
Total coliform bacteria and E. coli — annual minimum
Nitrates — northern Indiana corn belt counties (highest priority)
Arsenic — glacial outwash wells in Carroll, Cass, Miami, Wabash, and Howard counties
Iron and manganese — glacial drift aquifer wells throughout the state
PFAS — near Grissom ARB, Camp Atterbury, and Crane Naval Weapons Support Center
Volatile organic compounds — near industrial sites in the Indianapolis metropolitan fringe and Lake County
pH and hardness — calcium-rich limestone geology creates very hard water statewide
Common Contamination Risks in Indiana
Nitrate from agricultural sources — Indiana's corn belt agriculture creates extensive nitrate contamination in shallow glacial aquifers, particularly in northern Indiana counties
Arsenic from glacial outwash — specific glacial outwash deposits in north-central Indiana have naturally elevated arsenic concentrations from glacially ground rock minerals
Iron and manganese from glacial sediments — very common throughout Indiana's glaciated landscape
Bacterial contamination from livestock and septic — Indiana has high numbers of confined animal feeding operations; runoff and field drainage can contaminate nearby shallow wells
PFAS from military and industrial sources — multiple identified sites across the state
Contaminant Guides Relevant to IN Wells
PFAS
Synthetic Chemicals
EPA limit: 4 ppt
Lead
Heavy Metals
EPA limit: 15 ppb (action level)
Nitrates
Agricultural Chemicals
EPA limit: 10 mg/L
DBPs
Disinfection Byproducts
EPA limit: 80 µg/L (TTHMs) / 60 µg/L (HAA5)
Arsenic
Heavy Metals
EPA limit: 10 ppb
Hard Water
Minerals
EPA limit: No federal limit
Chlorine
Disinfection Chemicals
EPA limit: 4 mg/L (MRDL)
Microplastics
Emerging Contaminants
EPA limit: No federal limit
Bacteria
Microbial Contamination
EPA limit: Zero E. coli / < 1 coliform per 100 mL
Fluoride
Minerals
EPA limit: 4 mg/L (MCL) / 2 mg/L (Secondary MCL)
Chromium-6
Heavy Metals
EPA limit: 100 ppb (total chromium)
Copper
Heavy Metals
EPA limit: 1.3 mg/L (action level)
Radon
Radioactive Contaminants
EPA limit: No finalized MCL
Iron & Manganese
Minerals
EPA limit: 0.3 mg/L iron / 0.05 mg/L manganese (aesthetic SMCLs)
Atrazine
Agricultural Chemicals
EPA limit: 3 ppb (0.003 mg/L)
Uranium
Radioactive Contaminants
EPA limit: 30 µg/L (30 ppb)
Perchlorate
Industrial Chemicals
EPA limit: 0.056 mg/L (56 ppb)
VOCs
Industrial Chemicals
EPA limit: Varies by compound: benzene 5 ppb; TCE 5 ppb; PCE 5 ppb; vinyl chloride 2 ppb
Radium
Radioactive Contaminants
EPA limit: 5 pCi/L (combined Ra-226 + Ra-228)
Crypto & Giardia
Microbial Contamination
EPA limit: Zero (treatment technique standard)
Hydrogen Sulfide
Naturally Occurring Compounds
EPA limit: No MCL; Secondary MCL (aesthetic) of 0.05 mg/L
Selenium
Minerals
EPA limit: 50 ppb (0.05 mg/L)
Cadmium
Heavy Metals
EPA limit: 5 ppb (0.005 mg/L)
Mercury
Heavy Metals
EPA limit: 2 ppb (0.002 mg/L)
Barium
Heavy Metals
EPA limit: 2 mg/L
Find a Certified Lab in Indiana
Use the Indiana state-certified laboratory program to find accredited labs for private well testing. Always verify current certification before submitting samples.
IN Certified Lab Directory ↗Indiana Well Water FAQs
Related Pages
Data Sources & Provenance
All data on this page is sourced from official U.S. government or public datasets.
Quick Reference
State program
IN Certified Labs ↗EPA guidance
EPA Private Wells Program ↗State lab directory
IN Certified Labs ↗Minimum Annual Tests
Plus state-specific contaminants listed above
Other State Guides