Water hardness by utility
Every figure below was read from the utility's own water-quality report or water-quality page on 2026-10-16. There are 10 systems here rather than thousands because a system appears only once someone has actually read a value on an official page. Nothing is modelled and nothing is published at ZIP-code level.
- 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 by state
Arizona
- Phoenix, AZ City of Phoenix Water Services Department, 2025 report
Colorado
- Denver, CO Denver Water, 2025 report
Indiana
- Indianapolis, IN Citizens Energy Group (Indianapolis), 2025 report
Massachusetts
- Boston, MA Massachusetts Water Resources Authority (MWRA)
Nevada
- Las Vegas, NV Las Vegas Valley Water District, 2026 report
New Hampshire
- Manchester, NH Manchester Water Works, 2022 report
New York
- New York, NY New York City Department of Environmental Protection (NYC DEP), 2025 report
Oregon
- Portland, OR Portland Water Bureau, 2025 report
Texas
- Austin, TX Austin Water, 2025 report
- San Antonio, TX San Antonio Water System (SAWS)
Why the list is short
Hardness is not a regulated contaminant, so a utility is not required to publish it. Several large systems checked on 2026-10-16 publish no hardness figure at all in their current report, and they are not listed above because there was no number to list:
| Utility | What was checked | Why there is no page |
|---|---|---|
| Seattle Public Utilities | 2 official pages, 2026-10-16 | No hardness line in the 2025 Drinking Water Quality Report, and the Water Quality Analyses index page did not render its quarterly-analysis links to us. SPU's quarterly surface water analyses are the likely home of the figure; this is a page to add once one of those documents can be read directly. |
| City of Chicago Department of Water Management | 4 official pages, 2026-10-16 | The 2021 Water Quality Report carries no hardness line. The Comprehensive Chemical Analysis index and the CHI311 hardness article are rendered by scripts and returned no values or document links to us. Chicago's figure is most likely in a Comprehensive Chemical Analysis PDF; no page here until one is read. |
Two systems that do publish a figure publish it somewhere other than the annual report: San Antonio states it on a water-quality FAQ, and Boston's MWRA states it on a tap-water FAQ. Both are cited on their own pages. Reading your own report is covered in how to read a water quality report, and the methodology page lists every source and assumption.
What to do with a utility figure
Convert it before you use it
Reports publish mg/L or ppm, and sometimes ppb. Softener and appliance instructions want grains per gallon. The converter shows the arithmetic rather than hiding it.
Treat a range as a range
Indianapolis publishes 148 to 460 mg/L across its system. Averaging that into one number for a city page would throw away the most useful thing the report says.
Test your own tap if it matters
A utility figure is the water leaving the system, not the water at your fixture. For sizing equipment, a test at the tap beats any published figure, including the ones here.