According to the San Bernardino Municipal Water Department Consumer Confidence Report (2025 data), water from San Bernardino Municipal Water Department averages 14.2 grains per gallon of hardness, which the U.S. Geological Survey classes as very hard. Compare every city’s agency figure.
The San Bernardino Municipal Water Department reports that its entire supply is groundwater from the Bunker Hill Basin, and it lists the hardness as naturally occurring. The average is 242.2 mg/L, with samples from 130 to 330 mg/L. The department's service area does not follow the city line. State boundary data shows East Valley Water District serving parts of the city near Highland, and its report lists a lower average of 152 mg/L. Colton, Rialto and Loma Linda each publish their own water report, so a San Bernardino mailing address does not guarantee this figure.
What 14.2 gpg means
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. Very hard is the top band on the scale, and 14.2 sits well inside it. Very hard water leaves scale on fixtures, spots on glass and buildup inside water heaters.
The department prints its figure in mg/L. We converted it at 17.1 mg/L per grain, the factor water agencies use, which is why the card above says calculated rather than printed.
Where your water comes from
The San Bernardino Municipal Water Department reports that all of its supply is groundwater from the Bunker Hill Basin. Not every address with a San Bernardino mailing address is in the department's area. State boundary data shows ZIP codes 92401, 92405, 92408 and 92411 almost entirely inside it, while others, including 92404 and 92410, are shared with other suppliers. If your bill comes from another supplier, read that supplier's report instead.
San Bernardino's rule on water softeners
The department's Rule and Regulation No. 26, section 3.8, allows a residential softener only if it regenerates off site, or if it drains to the home's waste system and meets state standards. Those are regenerating only when needed, a third-party certified salt efficiency of at least 4,000 (hardness removed per pound of salt), and water-saving devices on every softened-water fixture. A C-55 or C-36 contractor also files a certification with the City Building Division.
The department's director may limit or prohibit sewer-discharging softeners after three specific findings, and we have not found that the director has made them. The rule covers the department's sewer customers only. Highland, Colton, Rialto and Loma Linda have their own sewer providers, and we have not reviewed their rules. This is a plain-words summary, not legal advice, so confirm before you buy.
All groundwater, and not always this department's
The Municipal Water Department pumps all of its water from the Bunker Hill Basin. Its 14.2 gpg is converted from a 242.2 mg/L average, with samples from 130 to 330 mg/L. Whether that figure is yours depends on who reads your meter. Homes near Highland may be on East Valley Water District, which lists a lower average, and Colton, Rialto and Loma Linda publish their own reports. The free water analysis reads the water at your tap, whichever agency sends it. If a system you already own has stopped keeping up, start with water softener repair. Otherwise, book below.
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Questions people ask
How hard is the water in San Bernardino?
The San Bernardino Municipal Water Department reports an average of 242.2 mg/L, which is 14.2 gpg. Samples in the report run from 130 to 330 mg/L. That is in the very hard band on the USGS scale.
Is the 14.2 figure printed by the water department or converted?
The department prints the figure in mg/L. We converted it at 17.1 mg/L per grain, the factor water agencies use, so the card at the top of this page says calculated.
Does the whole city get the same water?
Not necessarily. State boundary data shows ZIP codes 92401, 92405, 92408 and 92411 almost entirely inside the department's area. Others, including 92404 and 92410, are shared with other suppliers such as East Valley Water District. Your water bill names your supplier.
Where does San Bernardino's water come from?
The department's report says all of its supply is groundwater from the Bunker Hill Basin. It lists the hardness as naturally occurring.
Can I install a water softener in San Bernardino?
The department's Rule and Regulation No. 26 allows residential water softeners with conditions: off-site regeneration, or a unit that meets state equipment standards, with a C-55 or C-36 contractor's certification filed with the City Building Division. It is a conditional rule, not a ban. Confirm with the department before you buy.
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 San Bernardino?
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 San Bernardino, 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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