# San Francisco Water Systems by My Home Water System

> Published water hardness for San Francisco, CA, 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
- Hardness, SFPUC: Average 62 ppm, range 8.1-112 ppm (Calendar year 2025). Source: 2025 Annual Water Quality Report (City of San Francisco), https://www.sfpuc.gov/vi/sites/default/files/accounts-and-services/water-quality/water-quality-en-SF-2025.pdf
- USGS class, our reading of the published figures: soft to moderately hard. Classes: https://www.usgs.gov/water-science-school/science/hardness-water
- SFPUC disinfects with ultraviolet light and chlorine and keeps the water disinfected in the pipes with chloramine. Source: SFPUC 2025 Water Quality Report, https://www.sfpuc.gov/vi/sites/default/files/accounts-and-services/water-quality/water-quality-en-SF-2025.pdf
- Hetch Hetchy Reservoir supplies up to 85 percent of San Francisco water each year, with the rest from Bay Area reservoirs and a small amount of local groundwater. Source: SFPUC 2025 Water Quality Report, https://www.sfpuc.gov/vi/sites/default/files/accounts-and-services/water-quality/water-quality-en-SF-2025.pdf
- SFPUC says blending different sources through the year gave varying water quality. Source: SFPUC 2025 Water Quality Report, https://www.sfpuc.gov/vi/sites/default/files/accounts-and-services/water-quality/water-quality-en-SF-2025.pdf
- Sources last checked: 2026-10-27

## Pages
- [San Francisco water and quotes](https://sanfranciscowatersystems.com/): the answer, the sources, common questions
- [Water data as JSON](https://sanfranciscowatersystems.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.