Well Water Testing in Indiana — What to Test For and When

March 2, 2026

Having your own well means having direct responsibility for water quality. Indiana does not require routine testing of private wells, but regular testing is strongly recommended. Here’s what you need to know.

When to Test Your Well Water

Test immediately if:

• The well is newly drilled or significantly modified
• You notice changes in taste, odor, or color
• Flooding or surface runoff has reached the wellhead area
• Nearby land use has changed (new agriculture, spills, industrial activity)
• Family members experience unexplained gastrointestinal illness
• You’re buying a property with an existing well

Routine testing schedule:

• Annually: Bacteria (total coliform and E. coli), nitrates — these can change seasonally
• Every 3–5 years: Full panel including pH, hardness, iron, manganese, arsenic, and other local concerns
• At change of ownership: Full panel before purchasing a property served by a private well

Core Tests for All Indiana Well Owners

Total Coliform and E. coli

The most important test for a private well. Coliform bacteria indicate fecal contamination — a health risk that must be addressed immediately. Sources include septic system failures, surface runoff, and animals near the wellhead.

Safe level: Zero detectable coliforms or E. coli per 100 mL sample.

Nitrates

Nitrates are a significant concern in Indiana’s agricultural regions. High nitrate levels (above 10 mg/L as nitrogen, the EPA limit) pose serious health risks to infants under six months. Sources include fertilizer runoff, livestock waste, and septic systems.

Safe level: Below 10 mg/L (as N)

pH

Indiana groundwater ranges from slightly acidic (pH 6.0) to alkaline (pH 8.5). Low pH (acidic water) can corrode metal pipes and fixtures. High pH affects taste and can indicate high mineral content.

Target range: 6.5–8.5

Additional Tests Based on Local Conditions

Iron and Manganese

Common in Indiana groundwater, especially in glaciated areas. Causes staining of fixtures and laundry; doesn’t pose a direct health risk at typical levels but affects taste and appliance longevity.

Hardness

Indiana water tends to be moderately to very hard due to limestone geology. Hard water isn’t a health risk but can reduce appliance efficiency and soap effectiveness.

Arsenic

Naturally occurring arsenic is found in some Indiana bedrock wells, particularly in southern Indiana. EPA maximum contaminant level is 10 parts per billion. Test if you have a deep bedrock well in southern Indiana.

Radon in Water

Some Indiana groundwater sources contain dissolved radon, particularly from certain bedrock formations. Radon in water is a concern when water is used indoors (showering releases radon to air). Test if your area has elevated radon. Visit IN Radon Pros for licensed radon testing professionals who can test both air and water.

Volatile Organic Compounds (VOCs) and PFAS

If you live near industrial sites, dry cleaners, military bases, or fire training areas, test for VOCs and PFAS (per- and polyfluoroalkyl substances). PFAS contamination has been identified at several locations in Indiana. Contact IDEM for information on known contamination in your area.

Where to Get Your Water Tested

County health department: Many Indiana county health departments offer well water testing programs at low cost. This is the most accessible option for bacteria and nitrate testing.

State-certified laboratories: Indiana requires labs that test public water to be certified by IDEM. The same certification applies to private well testing. Look for IDEM-certified labs — your county health department can provide a list.

University Extension: Purdue University Extension offers water testing resources and guidance for Indiana homeowners.

What to Do If Results Are Abnormal

For bacteria contamination:

1. Do not drink the water until resolved
2. Shock-chlorinate the well (your well driller can do this)
3. Re-test 2 weeks after treatment
4. If contamination persists, investigate source (wellhead condition, nearby septic)

For high nitrates:

1. Do not give to infants under 6 months
2. Bottled water as interim solution
3. Consider a reverse osmosis filter or well deepening to access a cleaner aquifer

For other contaminants: Contact your county health department or IDEM for guidance specific to the contaminant type.

Proper Water Sample Collection

Results are only as good as the sample. For bacteria testing:

• Use a sterile container provided by your lab
• Run the cold water faucet nearest the wellhead for 5–10 minutes before sampling
• Do not touch the inside of the container or cap
• Refrigerate immediately; deliver within 6 hours of collection
• Avoid sampling during or immediately after heavy rain

Your county health department or testing lab will provide specific collection instructions.