Water softeners and filtration in San Diego, CA

What does City of San Diego Public Utilities publish about San Diego water?

The City of San Diego treats water at its Alvarado, Miramar and Otay plants and also buys treated water.

• Most of the supply is imported from the Colorado River and the State Water Project.

San Diego water by treatment plant: where each one serves, its own figures and how it is treated.

What does 54.4 to 285 mg/L mean for a San Diego home?

54.4 to 285 mg/L is about 3.2 to 16.7 grains per gallon. The low end, 54.4 mg/L, is 6 mg/L under the 60 mg/L top of the USGS soft class; San Diego's high end, 285 mg/L, is 105 mg/L over the 180 mg/L line where the USGS very hard class starts. (USGS hardness classes)

Which systems fit San Diego water?

How does a San Diego quote work?

1. Send a request from one of the 42 San Diego ZIP codes listed below.
2. An assessment at your home, where your tap can be checked against City of San Diego Public Utilities's published 54.4 to 285 mg/L.
3. You get a written quote listing what is included.
4. Installation and service by that company.

Common questions

How hard is the water in San Diego?

Total hardness, Alvarado plant reported by City of San Diego Public Utilities: Average 237 ppm (13.8 grains per gallon), range 203-270 ppm (Calendar year 2025). Total hardness, Miramar plant reported by City of San Diego Public Utilities: Average 242 ppm (14.1 grains per gallon), range 200-285 ppm (Calendar year 2025). Total hardness, Otay plant reported by City of San Diego Public Utilities: Average 243 ppm (14.2 grains per gallon), range 201-271 ppm (Calendar year 2025). Total hardness, purchased treated water reported by City of San Diego Public Utilities: Average 145 ppm (8.5 grains per gallon), range 54.4-232 ppm (Calendar year 2025).

Is San Diego water hard or soft?

Soft to very hard. The low end, 54.4 mg/L, is 6 mg/L under the 60 mg/L top of the USGS soft class; San Diego's high end, 285 mg/L, is 105 mg/L over the 180 mg/L line where the USGS very hard class starts.

How many grains per gallon is San Diego water?

In grains per gallon, as published: 13.8 grains per gallon (City of San Diego Public Utilities, total hardness, alvarado plant, Calendar year 2025); 14.1 grains per gallon (City of San Diego Public Utilities, total hardness, miramar plant, Calendar year 2025); 14.2 grains per gallon (City of San Diego Public Utilities, total hardness, otay plant, Calendar year 2025); 8.5 grains per gallon (City of San Diego Public Utilities, total hardness, purchased treated water, Calendar year 2025).

Where does San Diego tap water come from?

Most San Diego water is imported through the County Water Authority, mainly a Colorado River and State Water Project blend, with local reservoir water, treated at the Alvarado, Miramar and Otay plants. Source: City of San Diego 2025 Annual Drinking Water Quality Report.

Does San Diego water change over time?

The city says the share of water from each source changes through the year. Source: City of San Diego 2025 Annual Drinking Water Quality Report.

Is San Diego water treated with chlorine or chloramine?

San Diego uses chloramine to keep water disinfected in the pipes, after ozone or chlorine dioxide treatment at its plants. Source: City of San Diego 2025 Annual Drinking Water Quality Report. That matters when choosing a filter for a San Diego home: catalytic carbon is the activated-carbon type designed to adsorb chloramine (NDSU Extension, Filtration: Sediment, Activated Carbon, and Mixed Media). A softener leaves City of San Diego Public Utilities's disinfectant in the water.

How does San Diego water compare with nearby cities?

Published hardness in San Diego spans 54.4 to 285 mg/L. Nearby: Los Angeles 78 to 280 mg/L; Riverside 180 to 210 mg/L; San Francisco 8.1 to 112 mg/L.

Do I need a water softener in San Diego?

City of San Diego Public Utilities publishes 54.4 to 285 mg/L for San Diego, which reads as soft to very hard. A test at your house shows whether your tap matches it.

Is the water the same in every San Diego home?

4 published figures cover San Diego, from 1 utility; which applies depends on where you live. The water-by-area page breaks San Diego down further.

How much does a water softener cost in San Diego?

We publish no prices for San Diego. The installing company gives a written quote after an assessment at your home.

Who installs the system?

We have not named a local installing company for San Diego yet. We will tell you the company's name and ask you before your request is shared with anyone.

Is San Diego Water Systems part of the city or the water utility?

No. San Diego Water Systems is not affiliated with City of San Diego Public Utilities; it copies and links the published figures.

Is booking an assessment a purchase?

No, and a request commits you to nothing.

Which ZIP codes does this page cover?

92037, 92092, 92093, 92101, 92102, 92103, 92104, 92105, 92106, 92107, 92108, 92109, 92110, 92111, 92113, 92114, 92115, 92116, 92117, 92119, 92120, 92121, 92122, 92123, 92124, 92126, 92127, 92128, 92129, 92130, 92131, 92132, 92134, 92136, 92139, 92140, 92145, 92147, 92154, 92161, 92173, 92182

Compare published hardness in other cities on hard water by city.

Machine-readable facts: water.json. Summary for AI assistants: llms.txt.