Johnson County Water Guide
Straight answers about the water in Whiteland, New Whiteland, Greenwood and Franklin, with the sources. Written by Erick Barkley, licensed Indiana plumbing contractor #PC12600309.
How Hard Is the Water in Johnson County?
| Town | Water supplier | Hardness (2025 report) |
|---|---|---|
| Greenwood | Indiana American Water, Johnson County system | 358–382 ppm plant averages (about 21–22 gpg), range 291–431 ppm |
| Franklin | Indiana American Water, Johnson County system | 358–382 ppm plant averages (about 21–22 gpg), range 291–431 ppm |
| New Whiteland | Indiana American Water, Johnson County system | 358–382 ppm plant averages (about 21–22 gpg), range 291–431 ppm |
| Whiteland | Whiteland Water Works, buying from Indiana American Water | Not reported separately. Test at your tap. |
Anything over 180 ppm (10.5 grains per gallon) is "very hard," according to the U.S. Geological Survey.
How Hard Is Johnson County Water?
Very hard. Indiana American Water's Johnson County system, which serves Greenwood, Franklin and New Whiteland and sells water to Whiteland, reported average hardness of 358 to 382 ppm at its three treatment plants, about 21 to 22 grains per gallon, in its 2025 report. The U.S. Geological Survey classes anything over 180 ppm as very hard.
Do I Need a Water Softener in Johnson County?
Most homes on city water here benefit from one, because water at about 21 to 22 grains per gallon leaves scale on fixtures and inside water heaters. A free in-home test shows your exact number before you buy anything.
How Much Does a Water Softener Cost in Johnson County?
Salty Dog Plumbing's softener installs start at $1,500. The price depends on your hardness, household size and install location.
How Much Does a Reverse Osmosis System Cost?
Salty Dog Plumbing installs three RO drinking water systems at $600, $750 and $850.
How Much Does It Cost to Replace a Water Heater in Johnson County?
Salty Dog Plumbing's water heater replacements start at $1,650.
How Do I Convert Ppm to Grains per Gallon?
Divide by 17.1. For example, 376 ppm ÷ 17.1 ≈ 22 grains per gallon.
How Often Does a Backflow Need to Be Tested in Indiana?
At installation and at least once a year after that, by a registered cross-connection control device inspector. That's Indiana rule 327 IAC 8-10-8.
Who Can Test a Backflow Preventer in Indiana?
Only an inspector registered with the state, which takes 40 hours of training plus written and oral exams (327 IAC 8-10-11).
Why Does My Well Water Smell Like Rotten Eggs?
Usually hydrogen sulfide, which occurs naturally in Indiana groundwater. The Indiana Department of Health recommends testing private wells at least once a year.
Does Hard Water Damage Water Heaters?
Yes. Hardness minerals settle in the tank as scale, which makes the heater work harder and wear out sooner. Annual flushing and a softener both help.
Indiana American Water, 2025 Annual Water Quality Report, Johnson County Operations (PWS ID IN5241005)
Whiteland Water Works, 2025 Annual Drinking Water Quality Report (PWS ID IN5241009)
Town of Whiteland, Water Department
U.S. Geological Survey, Hardness of Water
327 IAC 8-10-8 and 8-10-11, Indiana Administrative Code
Indiana Department of Health, Sulfates and Sulfides in Well Water
Last updated: October 23, 2026