Hardness is on no federal list, so no utility has to publish it, and seventeen cities give seventeen different kinds of answer. Here they are ordered from the hardest published figure to the softest, with the figure each utility itself prints, and what the hardness band does to the size of the water treatment market in that city.
The band decides how many homes already own a softener. The softener's age decides how many are replaced this year. Your truck decides who gets the call.
Short answer
Of the seventeen cities the tour has read the water for, the top of the published range is 20 grains per gallon or more in Jacksonville and San Antonio, between 16 and 18 in Phoenix, Tampa, Las Vegas and Los Angeles, 13 to 14 in San Diego, Carlsbad and Houston, and 7 to 10 in Omaha, Dallas, Chicago, Austin and Orlando. Reno is 3 to 4 in fall and winter. Atlanta and New Orleans publish no figure at all. Every one of those numbers is the utility's own, in its own report or on its own website.
Hardness is dissolved calcium and magnesium, printed in grains per gallon (gpg) or milligrams per liter (mg/L). One grain per gallon is 17.1 mg/L. The U.S. Geological Survey (USGS) bands: soft under 3.5 gpg, moderately hard 3.5 to 7, hard 7 to 10.5, very hard above 10.5.
The market calculator's ownership rates, from Jeff Hubbard's dealer days: 85 percent of homes have a softener in a market over 20 grains, 70 percent at 10 to 20, 40 percent at 5 to 10, and 15 percent under 5. Salt-based softeners only.
The whole-house filter line does not move with hardness at all, because chlorine and chloramine are on every city system. A soft-water city still has a filter market.
The table
Ordered by the top of each utility's published range. Where a utility printed only one unit, the other is calculated at 17.1 mg/L per grain and marked. Classifications follow the USGS bands. A figure marked undated is one the utility publishes without a sampling year, and should be read as a typical value, not a measured annual result.
| City | Hardness as the utility publishes it | USGS band | Softener ownership band |
|---|---|---|---|
| Jacksonville, FL | 120 to 372 ppm (7 to 22 gpg), forty-one values by ZIP code, undated | Moderately hard to very hard | 5 to 10 up to over 20 |
| San Antonio, TX | 15 to 20 gpg (257 to 342 mg/L, calculated), undated | Very hard | 10 to 20 |
| Phoenix, AZ | 172 to 302 ppm (10 to 17.6 gpg), 2025 | Hard to very hard | 10 to 20 |
| Tampa, FL | 211 mg/L (12.3 gpg) annual average; 140 to 300 ppm seasonally, 2025 | Very hard | 10 to 20 |
| Las Vegas, NV | 280 ppm (16 gpg) in the 2025 report; 291 ppm (17 gpg) on the facts page | Very hard | 10 to 20 |
| Los Angeles, CA | 8.6 to 16.3 gpg by area (2022); 103 to 236 mg/L by source (2025) | Moderately hard to very hard | 5 to 10 up to 10 to 20 |
| San Diego, CA | 237 to 243 ppm (13.8 to 14.2 gpg) by plant; purchased water 145 ppm (8.5), 2025 | Hard to very hard | 10 to 20 |
| Carlsbad, CA | 3.5 to 13.5 gpg depending on the district and the desalination blend, 2025 | Soft to very hard | Under 5 up to 10 to 20 |
| Houston, TX | 43.5 to 229 ppm, average 135.5 (2.5 to 13.4 gpg, average 7.9, calculated), 2025 | Soft to very hard | 5 to 10 on the average |
| Omaha, NE | About 170 mg/L (10 gpg), lime softened, undated | Hard | 5 to 10 |
| Dallas, TX | 120 to 155 mg/L (7.0 to 9.1 gpg), 2023 memo | Moderately hard to hard | 5 to 10 |
| Chicago, IL | 130 to 150 mg/L (7.6 to 8.8 gpg), 2018 page | Hard | 5 to 10 |
| Austin, TX | 70 to 126 ppm (4.1 to 7.4 gpg), average 93 (5.4), 2025 | Moderately hard to hard | 5 to 10 |
| Orlando, FL | 129 ppm (7 gpg) average, undated | Hard | 5 to 10 |
| Reno, NV | 3 to 4 gpg (50 to 68 mg/L), fall and winter only; no summer figure published | Soft to moderately hard | Under 5 |
| Atlanta, GA | Not published anywhere the utility writes | Unknown | Test it |
| New Orleans, LA | Not published anywhere the utility writes | Unknown | Test it |
In Roger Wakefield's own field tests in Dallas homes, readings typically run 8 to 12 gpg, above the city's published range. Which is the point of the last column: a published figure tells you the band a market is probably in. The tap tells you the house. Every row, with the utility's document linked, is on water hardness by city.
What the band buys
Take the same 100,000 single-family homes and move them between hardness bands, using the ownership rates the market calculator runs on. The replacements follow the installed base, because about 8 in 100 softeners are replaced every year on a 12.5-year life.
| Hardness band | Homes with a softener | Installed, per 100,000 homes | Replaced a year |
|---|---|---|---|
| Over 20 gpg | 85 percent | 85,000 | 6,800 |
| 10 to 20 gpg | 70 percent | 70,000 | 5,600 |
| 5 to 10 gpg | 40 percent | 40,000 | 3,200 |
| Under 5 gpg | 15 percent | 15,000 | 1,200 |
Ownership rates are Jeff Hubbard's assumptions from his dealer days and are labeled as assumptions on the calculator; they count salt-based softeners only. The whole-house filter line, 22 percent of homes on a 10-year life, is the same in every band. A soft-water city has a smaller softener market and the same filter market, which is why "our water is fine" is an answer about one product line, not about water treatment. Run your own homes on the market calculator.
The four that do not fit a table
JEA publishes no citywide figure. It publishes a table of forty-one ZIP codes, from 7 grains in 32234 to 22 in 32081, each the average of the wells serving that plant. A technician who knows the ZIP knows the band before he knocks.
The district's own facts page says 17 grains under one heading and 16 under another; the 16 is the one in the current annual report. North Las Vegas and Henderson are separate systems with different water.
The only version in grains per gallon by neighborhood is from 2022. The 2025 figures are by source, and the utility says plainly that most areas can receive any of the supplies during repairs.
Three to four grains in fall and winter, mostly treated surface water. No summer figure, because in summer a home may be on a blend of surface and well water. That is a utility refusing to give one number to something that is not one number.
None of those utilities is doing anything wrong. Hardness has no maximum contaminant level because it is not a health concern, so a utility that publishes it is volunteering it. The absence is a gap in the regulation, not in the paperwork, and it is the reason the class teaches field testing before anything else.
Watch it
Questions
Of the seventeen cities the tour has read the water for, the highest published figures are Jacksonville, up to 22 grains per gallon in one ZIP code, and San Antonio, 15 to 20 grains. Phoenix, Tampa, Las Vegas and Los Angeles all publish figures that reach 16 to 18 grains. Every figure is the utility's own.
No. Hardness has no maximum contaminant level because it is not a health concern, and it appears on neither the primary nor the secondary federal drinking water regulations. A utility that publishes it is volunteering it, and two of the seventeen cities checked publish nothing at all.
On the market calculator's rates, 85 percent of homes have a softener in a market over 20 grains, 70 percent at 10 to 20, 40 percent at 5 to 10 and 15 percent under 5. Replacements follow the installed base at about 8 in 100 a year. The whole-house filter market does not move with hardness, because chlorine and chloramine are on every city system.
Use it to know the band your market is probably in, then test the house. Published figures are system-wide ranges, sometimes from two plants, sometimes four years old, and in Roger Wakefield's own Dallas field tests the tap typically reads above the city's published range.
Start with your utility's annual water quality report, then its website, since four of the seventeen publish hardness somewhere other than the report. If it is not published anywhere, test it at the tap; the market calculator asks for a hardness band for exactly that reason.
Sources
Checked in November 2026. Every hardness figure is the utility's own, as read and linked on the water hardness by city page; ownership rates and the replacement rate are the market calculator's, labeled as assumptions there.
Written by Roger Wakefield, Texas Master Plumber
45 years in the trade and LEED AP. Published . More about Roger or read how to read a water quality report on rogerwakefield.com.
Keep going
The first class ran in Dallas, November 3-5. The next HALO Water Tour dates are coming soon. Apply now and you'll hear first. Carlsbad returns in early 2027 with the dates announced on the Carlsbad page first.