Indianapolis, IN water hardness
Citizens Energy Group (Indianapolis) publishes an average hardness of 317 mg/L (19 grains per gallon, also its own figure) for its system, in its Citizens Energy Group — Indianapolis and Morgan County Consumer Confidence Report Data 2025. On the USGS scale that is very hard water.
The published figure, exactly as it appears
This is the hardness line transcribed from the source, with nothing added:
Hardness (ppm) | SMCL N/A | Average of All Samples 317 ppm 19 grains/gal | Maximum of All Samples 460 ppm 27 grains/gal | System Wide Range 148 - 460 ppm 8.7 - 27 grains/gal | Erosion of natural deposits; leaching
Citizens Energy Group (Indianapolis), Citizens Energy Group — Indianapolis and Morgan County Consumer Confidence Report Data 2025
Units as published: ppm, with grains/gal given alongside. What kind of figure it is: an average with a range. Retrieved 2026-10-16.
Indianapolis hardness in mg/L and grains per gallon
Water-quality reports use mg/L (identical to ppm). Softener instructions and plumbing specifications use grains per gallon. Both are below. Where a figure is our arithmetic rather than the utility's own number, it says so.
| Figure | mg/L (ppm) | Grains per gallon | Whose number |
|---|---|---|---|
| Published average | 317 | 19 | both published by the utility |
| Low end of published range | 148 | 8.7 | mg/L published, gpg is our conversion |
| High end of published range | 460 | 27 | mg/L published, gpg is our conversion |
| Plotted on the scale above | 317 | 18.5 | published average; the gpg here is our conversion at 17.1, so it can differ slightly from a utility’s own rounded gpg figure |
The conversion, both ways: gpg = mg/L ÷ 17.1 and mg/L = gpg × 17.1. Worked for this system: 317 ÷ 17.1 = 18.5 gpg. The converter does °dH and °f as well, and why the factor is 17.1 explains where the number comes from.
What this figure does not tell you
Service area and source water
| Utility | Citizens Energy Group (Indianapolis) |
|---|---|
| Public water system ID | IN5249004 |
| Service area as published | Indianapolis (PWS IN5249004); the same report page also covers Morgan County (PWS IN5255019) and the published figures are labelled system wide, sampled at the treatment plants. |
Provenance of every number on this page
| Source document | Citizens Energy Group — Indianapolis and Morgan County Consumer Confidence Report Data 2025 |
|---|---|
| Source URL | https://info.citizensenergygroup.com/water/quality/indianapolis-and-morgan-county |
| Published by | Citizens Energy Group |
| Report year | 2025 |
| Year note | Hardness sits under 'SECONDARY DRINKING WATER STANDARDS & UNREGULATED CONTAMINANTS (Sampled at Treatment Plant)'. The page notes that some of its data, though accurate, is more than one year old. |
| Retrieved | 2026-10-16 |
| Classification bands | USGS Water Science School, retrieved 2026-10-16 |
Notes the report forces on this page
- The range is explicitly labelled 'System Wide Range' and spans a 3:1 spread, 148 to 460 ppm. On a system like this one, a single number for the city would be misleading.
- The report's maximum of all samples equals the top of the system-wide range.
If you are sizing a softener for Indianapolis water
At 19 gpg, the sizing arithmetic starts from your household's water use, not from the hardness alone. The calculator below is pre-filled with this system's figure and every other input is an editable assumption.
Whether a softener is worth installing at this hardness is a judgement, not arithmetic, and it is not one this site makes for you. Nothing here has been tested by the author.
Where Indianapolis sits against other verified systems
- Portland, OR 9 mg/L 0.5 gpg Soft
- Boston, MA 16 mg/L 1 gpg Soft
- Manchester, NH 17.9 mg/L 1 gpg Soft
- New York, NY 32 mg/L 2 gpg Soft
- Austin, TX 93 mg/L 5.4 gpg Moderately hard
- Denver, CO 105 mg/L 6.1 gpg Moderately hard
- Phoenix, AZ 237 mg/L 13.9 gpg Very hard
- Las Vegas, NV 280 mg/L 16 gpg Very hard
- San Antonio, TX 299.3 mg/L 17.5 gpg Very hard
- Indianapolis, IN 317 mg/L 19 gpg Very hard
mg/L as calcium carbonate. Each classification band is drawn the same width, so the axis is not linear in mg/L.
Systems with similar published hardness
- San Antonio, TX San Antonio Water System (SAWS), 299.3 mg/L (17.5 gpg)
- Las Vegas, NV Las Vegas Valley Water District, 280 mg/L (16.4 gpg)
- Phoenix, AZ City of Phoenix Water Services Department, 237 mg/L (13.9 gpg)
- Denver, CO Denver Water, 105 mg/L (6.1 gpg)
All 10 verified systems How to find hardness in your own utility's report If you are on a well instead