Water hardness by city
Water hardness for US cities from each local utility's own water quality report, with the report year and a link, to set a softener or dishwasher.
San Antonio (typically 15–20 gpg) and Las Vegas (280 mg/L average) have very hard water, and most of Phoenix's range (172–302 mg/L) is very hard. Houston's average (135.5 mg/L) is hard, and Austin's (93 mg/L) is moderately hard. Find your city in the table below, then read its page to understand scale.
Cities
| City | Utility | Hardness (as published) | USGS class | Source year |
|---|---|---|---|---|
| Austin, TX | Austin Water | 93 mg/L · 5.4 gpg | Moderately hard | 2025 report |
| Houston, TX | City of Houston (Main System) | 135.5 mg/L · ≈7.9 gpg* (range 43.5–229) | Hard | 2025 report |
| Las Vegas, NV | Las Vegas Valley Water District | 280 mg/L · 16 gpg | Very hard | 2026 report (2025 data) |
| Phoenix, AZ | City of Phoenix Water Services | No average; range 172–302 mg/L · 10–17.6 gpg | Very hard (low end: hard) | 2025 report |
| San Antonio, TX | San Antonio Water System (SAWS) | No average; typical 15–20 gpg (≈257–342 mg/L*) | Very hard | SAWS FAQ (undated) |
Compare Texas cities on the Texas hub.
Cities by state
Texas (Austin, Houston, San Antonio), Arizona (Phoenix) and Nevada (Las Vegas).
How we get the numbers
- We open the utility's own documents. Usually that is the annual Water Quality Report (also called a Consumer Confidence Report). If the report has no hardness figure, we use the utility's official FAQ or data page and say so.
- We copy the total hardness exactly as stated: average, range, units and year.
- We convert units only where the utility did not (1 gpg = 17.1 mg/L) and say so.
- We classify with the USGS scale: soft, moderately hard, hard, very hard.
- We link each utility's own document behind its figures and show the date we last checked it.
More detail is on the method page. Switch units with the gpg ↔ mg/L converter.
What water hardness is
Hardness is the amount of dissolved calcium and magnesium in water. It causes white scale in kettles and on shower glass, spots on dishes, and weaker soap lather. USGS describes it as “not a health concern, but it can be a nuisance.”