Austin, TX water hardness
Austin Water publishes an average hardness of 93 mg/L (5.4 grains per gallon, also its own figure) for its system, in its Austin Water 2025 Water Quality Report. On the USGS scale that is moderately hard water.
The published figure, exactly as it appears
This is the hardness line transcribed from the source, with nothing added:
Total Hardness (as CaCO3) — Low 70 ppm (mg/L) [4.1 gpg], High 126 ppm (mg/L) [7.4 gpg], Average 93 ppm (mg/L) [5.4 gpg]
Austin Water, Austin Water 2025 Water Quality Report
Units as published: ppm (mg/L), with gpg given alongside. What kind of figure it is: an average with a range. Retrieved 2026-10-16.
Austin hardness in mg/L and grains per gallon
Water-quality reports use mg/L (identical to ppm). Softener instructions and plumbing specifications use grains per gallon. Both are below. Where a figure is our arithmetic rather than the utility's own number, it says so.
| Figure | mg/L (ppm) | Grains per gallon | Whose number |
|---|---|---|---|
| Published average | 93 | 5.4 | both published by the utility |
| Low end of published range | 70 | 4.1 | mg/L published, gpg is our conversion |
| High end of published range | 126 | 7.4 | mg/L published, gpg is our conversion |
| Plotted on the scale above | 93 | 5.4 | published average; the gpg here is our conversion at 17.1, so it can differ slightly from a utility’s own rounded gpg figure |
The conversion, both ways: gpg = mg/L ÷ 17.1 and mg/L = gpg × 17.1. Worked for this system: 93 ÷ 17.1 = 5.4 gpg. The converter does °dH and °f as well, and why the factor is 17.1 explains where the number comes from.
What this figure does not tell you
Service area and source water
| Utility | Austin Water |
|---|---|
| Service area as published | Austin Water's drinking water service area. The report publishes one set of system figures, not per-neighbourhood values. |
Provenance of every number on this page
| Source document | Austin Water 2025 Water Quality Report |
|---|---|
| Source URL | https://www.austintexas.gov/water/water-quality-reports |
| Published by | Austin Water, City of Austin |
| Report year | 2025 |
| Year note | Hardness row carries the report's note 'Sampled in 2025 unless noted differently.' |
| Retrieved | 2026-10-16 |
| Classification bands | USGS Water Science School, retrieved 2026-10-16 |
Notes the report forces on this page
- Austin Water's own report states the conversion as about 17.1 ppm per grain per gallon, which matches the factor used across this site.
If you are sizing a softener for Austin water
At 5.4 gpg, the sizing arithmetic starts from your household's water use, not from the hardness alone. The calculator below is pre-filled with this system's figure and every other input is an editable assumption.
Whether a softener is worth installing at this hardness is a judgement, not arithmetic, and it is not one this site makes for you. Nothing here has been tested by the author.
Where Austin sits against other verified systems
- Portland, OR 9 mg/L 0.5 gpg Soft
- Boston, MA 16 mg/L 1 gpg Soft
- Manchester, NH 17.9 mg/L 1 gpg Soft
- New York, NY 32 mg/L 2 gpg Soft
- Austin, TX 93 mg/L 5.4 gpg Moderately hard
- Denver, CO 105 mg/L 6.1 gpg Moderately hard
- Phoenix, AZ 237 mg/L 13.9 gpg Very hard
- Las Vegas, NV 280 mg/L 16 gpg Very hard
- San Antonio, TX 299.3 mg/L 17.5 gpg Very hard
- Indianapolis, IN 317 mg/L 19 gpg Very hard
mg/L as calcium carbonate. Each classification band is drawn the same width, so the axis is not linear in mg/L.
Systems with similar published hardness
- Denver, CO Denver Water, 105 mg/L (6.1 gpg)
- New York, NY New York City Department of Environmental Protection (NYC DEP), 32 mg/L (1.9 gpg)
- Manchester, NH Manchester Water Works, 17.9 mg/L (1 gpg)
- Boston, MA Massachusetts Water Resources Authority (MWRA), 16 mg/L (0.9 gpg)
All 10 verified systems How to find hardness in your own utility's report If you are on a well instead