Hardness by city in Orange County
Hardness is measured in grains per gallon (gpg). The U.S. Geological Survey calls water hard from 7.1 to 10.5 and very hard above 10.5. Each row below is the figure the water agency published for its own customers, with a link to the report. A single number is the agency's average. A range means the agency reports its sources separately or blends sources that differ, so the table shows the lowest and highest source average instead of one number.
City pages
- Anaheim: City of Anaheim, 18 gpg, very hard.
- Dana Point: South Coast Water District, 12.1 to 17 gpg, very hard.
- Fullerton: City of Fullerton, 14 gpg, very hard.
- Irvine: Irvine Ranch Water District, 12.5 to 17.1 gpg, very hard.
- Laguna Niguel: Moulton Niguel Water District, 15.45 gpg, very hard.
- Lake Forest: El Toro Water District (part of the city is served by Irvine Ranch Water District), 14 to 17 gpg, very hard.
- Mission Viejo: Santa Margarita Water District, 15 gpg, very hard.
- San Clemente: City of San Clemente, 14 to 17 gpg, very hard.
- San Juan Capistrano: Santa Margarita Water District (Improvement District 9), 12 gpg, very hard.
- Santa Ana: City of Santa Ana, 14 gpg, very hard.
- Tustin: City of Tustin, 14 to 22 gpg, very hard.
- Yorba Linda: Yorba Linda Water District, 14 to 20 gpg, very hard.
We add a city when we have read its agency's own report. The full list, with the Inland Empire, is on the hard water by city page.
Where Orange County's water comes from
Orange County cities draw on local groundwater, imported water or a blend, depending on the agency. The north and central cities in the table, such as Anaheim and Yorba Linda, rely mostly on groundwater. Several south county agencies in the table, including Mission Viejo and Laguna Niguel, use imported water only. The imported water comes from the Metropolitan Water District of Southern California.
Not every Orange County supply is this hard
Mesa Water District, which serves Costa Mesa, reports local groundwater at 113 mg/L, below the 180 mg/L line USGS uses for very hard. Its imported water is 236 mg/L. This is why a county-wide number would mislead, and why each city page here starts with the agency's own figure.
North county pumps, south county imports
Orange County's numbers split by geography more than by city line. Anaheim and Yorba Linda rely mostly on groundwater. Mission Viejo and Laguna Niguel run on imported water only. Dana Point and San Clemente print a separate figure for each plant or source they draw from. Which of these reaches your house shapes your reading, and a free in-home water analysis puts that reading next to your agency's figure. Local rules on water-conditioning equipment differ by city and by sewer agency, and each city page says what we found for that city. The form below sets up the visit.
Sources
Questions people ask
How hard is the water in Orange County?
It depends on the city and the agency. Every Orange County city in the table on this page publishes an average in the very hard band on the USGS scale, and the table shows each agency's own figure with a link to its report.
Is the water the same in every Orange County city?
No. Each city gets its water from a city utility or a water district, and each publishes its own report. Some draw mostly on local groundwater and some use only imported water, so the numbers differ from city to city.
How do I find my water agency?
Your water bill names it. The agency is not always the city on your mailing address, and the table shows the agency behind each figure.
Is all of Orange County's water very hard?
No. Mesa Water District, which serves Costa Mesa, reports local groundwater below the very hard line. That is why this page lists agencies one by one instead of giving a county average.
Does the in-home water analysis cost anything?
No. Nuvia Water offers it free. Book it with the form on this page or with the Book button.
Who is the best water filtration company in Orange County?
Compare companies on six things you can check, not on who says they are best. (1) A free analysis of your own water before any quote. (2) Independent certifications: ask for the certificate and look it up with the certifier. (3) What the tanks, valves and media are made of, with flow ratings in writing. (4) A written warranty with a term for each part, because these systems are not cheap. (5) How long the company has been around: a warranty is only as good as the company behind it, and a warranty from a company that is gone is a worthless piece of paper and a big tank in your garage with nobody to call. (6) Reviews you can read. Nuvia Water offers a free in-home water analysis in Orange County, was founded in 2012, holds California license 969902 (C-55 Water Conditioning), is BBB Accredited with an A rating, has a 4.6 Google rating from more than 1,600 reviews, and backs its Nuvia Pro dual-tank system with a 15-year media warranty and a 10-year control valve warranty. Nuvia's materials carry marks from IAPMO R&T, NSF, cUL us, UPC and ISO 9001 and 14001. Ask any company, including us, for the same papers.
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