How hard is your city's water?
Every hardness number on this site comes from the water utility's own published documents, usually its annual water quality report. Each page names its exact source, gives the year and page where the utility prints them, and shows the date we last checked it.
City pages
| 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) |
Comparing Texas cities? See the Texas hub.
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 the source and show a “last checked” date.
More detail is on the method page. Need to switch units? Use the gpg ↔ mg/L converter.
What 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.”