Updated November 1, 2026

Indianapolis tap water: some of the hardest big-city water in this guide

If your shower head clogs and your kettle grows a white crust, you're not imagining it. Citizens Water says its hardness averages 320 ppm as calcium carbonate, or 19 grains per gallon. That's several times the levels in Raleigh, Seattle or San Francisco.

A system of rivers, reservoirs and wells

Citizens Energy Group serves Indianapolis and Morgan County, and through Citizens Westfield, parts of Hamilton County. Its supply is a patchwork:

• The West Fork of the White River feeds the White River and White River North surface plants. Morse Reservoir near Noblesville stores water to keep the river reliable.
• Fall Creek is a second river source. Geist Reservoir stores water upstream so flow stays steady for the Fall Creek and White River plants.
• Eagle Creek Reservoir supplies the T.W. Moses treatment plant.
• Six groundwater plants (White River North, Geist Station, Harding Station, South Well Field, Harbour and Ford Road) treat aquifer water for smaller areas, and some wells run part-time to boost the surface plants.
• Westfield has three groundwater plants of its own (River Road, Cherry Tree and Greyhound Pass) and also buys some water.

Groundwater usually carries more minerals than surface water, which is a big reason hardness varies across the metro.

Hardness and minerals by the numbers

At this hardness, a softener usually pays for itself through longer water heater and appliance life. Size one with our softener sizing calculator. At 19+ gpg salt is a real recurring cost, so price it with the salt cost calculator.

Lead: a long replacement job

Citizens says water leaving its plants and traveling through its mains is free of lead. The risk is in service lines and home plumbing. In 2025 the Indianapolis and Morgan County area tested 106 homes. Two were above the 15 ppb action level, the 90th percentile was 4.7 ppb and the highest result was 19 ppb. The utility's replacement program covers an estimated 55,000 to 75,000 lead-containing customer lines, so for many households a certified lead filter is a sensible stopgap until the crew arrives.

River water, disinfection and what else turned up

Because surface water feeds most of the city, disinfection byproducts run higher than at groundwater systems. In Indianapolis and Morgan County, total trihalomethanes had a highest running average of 58 ppb (samples 22–70, limit 80) and HAA5 38 ppb (12–40, limit 60). Both are in compliance. The disinfectant is chloramine. Cryptosporidium and Giardia, which can occur in the White River, Fall Creek and Eagle Creek, weren't found in finished water. Nitrate averaged 1.1 ppm with a maximum of 4.0 (limit 10).

PFAS testing at the plants found traces of two compounds without federal limits. PFBS averaged 0.73 ppt (max 2.9) and PFHxA 0.63 ppt (max 2.5). The other PFAS on the test list weren't detected. Citizens also sampled for EPA's UCMR 5 (29 PFAS plus lithium) in May and November 2025 and will share results on request at 317-924-3311.