Water hardness and water treatment in California
Published drinking water hardness for 4 California cities, copied from each city's utility with its period and source. Pick your city for the full facts and to request a quote.
- Los Angeles: 6 published figures from LADWP. That reads as moderately hard to very hard.
- Riverside: Average 197 mg/L (12 grains per gallon), range 180-210 mg/L, Calendar year 2025, from Riverside Public Utilities. That reads as hard to very hard.
- San Diego: 4 published figures from City of San Diego Public Utilities. That reads as soft to very hard.
- San Francisco: Average 62 ppm, range 8.1-112 ppm, Calendar year 2025, from SFPUC. That reads as soft to moderately hard.
What should I compare?
Water softenerFor scale and hard water.Whole-home filterFor chlorine taste and odor.Reverse osmosisFor drinking water at one tap.
The U.S. Geological Survey classes water above 180 mg/L as calcium carbonate as very hard (USGS). We are not a water utility.