# Cincinnati Water Systems by My Home Water System

> Published water hardness for Cincinnati, OH, copied from the utility's own reports, and a way to request a written water treatment quote from one local company. Not a water utility.

## Water facts, as published
- Average hardness, Miller Plant, Greater Cincinnati Water Works: Average 126 mg/L (7 grains per gallon) (Undated FAQ on the page for the 2025 report). Source: Water Quality Reports (GCWW), Frequently Asked Questions: How hard is GCWW's water?, https://www.cincinnati-oh.gov/water/water-quality-and-treatment/water-quality-reports/
- Average hardness, Bolton Plant, Greater Cincinnati Water Works: Average 140 mg/L (8 grains per gallon) (Undated FAQ on the page for the 2025 report). Source: Water Quality Reports (GCWW), Frequently Asked Questions: How hard is GCWW's water?, https://www.cincinnati-oh.gov/water/water-quality-and-treatment/water-quality-reports/
- USGS class, our reading of the published figures: hard. Classes: https://www.usgs.gov/water-science-school/science/hardness-water
- Greater Cincinnati Water Works treats with ultraviolet light and chlorine.
- The utility does not say which plant serves which part of the city.
- Greater Cincinnati Water Works treats with ultraviolet light and chlorine. Source: Greater Cincinnati Water Works water quality reports page, https://www.cincinnati-oh.gov/water/water-quality-and-treatment/water-quality-reports/
- About 88 percent of Cincinnati water is Ohio River water from the Miller plant, and the rest is groundwater from the Great Miami Buried Valley Aquifer. Source: Greater Cincinnati Water Works water quality reports page, https://www.cincinnati-oh.gov/water/water-quality-and-treatment/water-quality-reports/
- Sources last checked: 2026-10-27

## Pages
- [Cincinnati water and quotes](https://cincinnatiwatersystems.com/): the answer, the sources, common questions
- [Water data as JSON](https://cincinnatiwatersystems.com/water.json)
- [Water softeners](https://www.myhomewatersystem.com/water-softeners/), [whole-home filtration](https://www.myhomewatersystem.com/whole-home-filtration/), [reverse osmosis](https://www.myhomewatersystem.com/reverse-osmosis/)
- [Hard water by city](https://www.myhomewatersystem.com/hard-water-by-city/): published hardness for every city we cover

## Status
- Not taking requests yet. No prices are published; quotes come after an assessment at the home.
- Run by My Home Water System, operated by Aidren LLC.