# Los Angeles Water Systems by My Home Water System

> Published water hardness for Los Angeles, 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
- Total hardness, Los Angeles Aqueduct plant, LADWP: Average 103 mg/L, range 96-117 mg/L (Calendar year 2025). Source: Drinking Water Quality Report 2025 (LADWP), Table III, https://www.ladwp.com/sites/default/files/2026-07/2026_DWQR_Print_Rev2_Digital-remediated.pdf
- Total hardness, northern wells, LADWP: Average 115 mg/L, range 78-151 mg/L (Calendar year 2025). Source: Drinking Water Quality Report 2025 (LADWP), Table III, https://www.ladwp.com/sites/default/files/2026-07/2026_DWQR_Print_Rev2_Digital-remediated.pdf
- Total hardness, southern wells, LADWP: Average 116 mg/L, range 83-159 mg/L (Calendar year 2025). Source: Drinking Water Quality Report 2025 (LADWP), Table III, https://www.ladwp.com/sites/default/files/2026-07/2026_DWQR_Print_Rev2_Digital-remediated.pdf
- Total hardness, MWD Weymouth plant, LADWP: Average 234 mg/L, range 189-280 mg/L (Calendar year 2025). Source: Drinking Water Quality Report 2025 (LADWP), Table III, https://www.ladwp.com/sites/default/files/2026-07/2026_DWQR_Print_Rev2_Digital-remediated.pdf
- Total hardness, MWD Diemer plant, LADWP: Average 236 mg/L, range 191-280 mg/L (Calendar year 2025). Source: Drinking Water Quality Report 2025 (LADWP), Table III, https://www.ladwp.com/sites/default/files/2026-07/2026_DWQR_Print_Rev2_Digital-remediated.pdf
- Total hardness, MWD Jensen plant, LADWP: Average 140 mg/L, range 137-142 mg/L (Calendar year 2025). Source: Drinking Water Quality Report 2025 (LADWP), Table III, https://www.ladwp.com/sites/default/files/2026-07/2026_DWQR_Print_Rev2_Digital-remediated.pdf
- USGS class, our reading of the published figures: moderately hard to very hard. Classes: https://www.usgs.gov/water-science-school/science/hardness-water
- In 2025 the Aqueduct supplied 44 percent and Metropolitan Water District water 52 percent.
- LADWP's FAQ gives older 2022 figures by area: about 8.6 grains per gallon in the San Fernando Valley and western Los Angeles, and about 16.3 in eastern Los Angeles and the Harbor.
- LADWP disinfects its drinking water with chloramine. Source: LADWP 2026 Drinking Water Quality Report, https://www.ladwp.com/sites/default/files/2026-07/2026_DWQR_Print_Rev2_Digital-remediated.pdf
- In 2025, 44 percent of LADWP water came from the Los Angeles Aqueduct, 52 percent was bought from the Metropolitan Water District (State Water Project and Colorado River), 1 percent was local groundwater and 3 percent was recycled water. Source: LADWP 2026 Drinking Water Quality Report, https://www.ladwp.com/sites/default/files/2026-07/2026_DWQR_Print_Rev2_Digital-remediated.pdf
- LADWP reports by community zone, and says the sources serving a zone can change with operations and supply, so water differs across the city. Source: LADWP 2026 Drinking Water Quality Report, https://www.ladwp.com/sites/default/files/2026-07/2026_DWQR_Print_Rev2_Digital-remediated.pdf
- Sources last checked: 2026-10-27

## Pages
- [Los Angeles water and quotes](https://losangeleswatersystems.com/): the answer, the sources, common questions
- [Water data as JSON](https://losangeleswatersystems.com/water.json)
- [Los Angeles water by area](https://losangeleswatersystems.com/by-area/): where each area or utility serves, its own figures and treatment
- [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
- Taking requests. No prices are published; quotes come after an assessment at the home.
- Run by My Home Water System, operated by Aidren LLC.