How hard is your water?
Find your city's water hardness in GPG & PPM, see the source and tier, and get a treatment recommendation.
Very Hard
Hard
Moderate
Soft
Browse by state
Pick your state to see every city's hardness — or search above for a single city.
Browse by province & territory
Canadian cities, from the soft mountain water of British Columbia to the hard prairie aquifers of Alberta and Saskatchewan.
Every city, on one map
539 cities across the US and Canada, color-coded by hardness. Hover a dot for the exact GPG, click to open the city's page.
Prefer a single state? Browse every state & province map →
Hardest cities
The 10 highest-GPG cities in our dataset. See the full ranked list →
Acton, ON
Very HardAssiniboia, SK
Very HardAnaheim, CA
Very HardBarrie, ON
Very HardAmarillo, TX
Very HardAllentown, PA
Very HardAirdrie, AB
Very HardBallantrae, ON
Very HardAllen, TX
Very HardAnnaheim, SK
Very HardThe water hardness scale
Hardness is measured in grains per gallon (GPG) or parts per million (ppm). Here's what each tier means.
Low scale buildup. Soap lathers easily. Rarely needs softening.
Example: San Francisco, CA (1.5 GPG)
Some spotting and scale. Consider softening above ~7.
Example: Denver, CO (5.7 GPG)
Visible scale on fixtures. Softener typically pays off.
Example: New Orleans, LA (9 GPG)
Heavy scale. Shortens appliance life. Softener recommended.
Example: Las Vegas, NV (16.4 GPG)
Hard water? Here's what to do
Read the full 2026 softener guide
Salt-based vs salt-free, sizing, cost, and the models actually worth buying.
Best Water Softeners 2026Size it correctly
The grain-capacity math that prevents buying a system that's too big or too small.
Softener sizing guideTest your own water
Confirm your exact hardness at the tap — municipal averages can vary by season.
How to test hardnessWhy some numbers deserve a grain of salt
Search a smaller city and you're likely to find two sites listing different hardness figures — or showing a number for a city where the utility has never published one. Water hardness has no legal reporting requirement, so wherever a utility stays quiet, other sites quietly fill the gap.
Most of the time those figures aren't measured. They're estimated from a neighboring system, copied from another aggregator, or simply made up to look authoritative. We'd tell you to take them with a grain of salt — which is fitting, because the calcium and magnesium carbonate that make water "hard" are, literally, salts. A "10-grain" softener is named for the grains of dissolved mineral salt it removes.
What we do instead.
- Primary sources only. We cite the utility's own water-quality report, a state or provincial health department, or USGS/EWG data — never a vendor, never a water-softener lead-gen site.
- We read the actual report. If hardness isn't in it, we mark the city "not published" rather than hand you a guess.
- Every number is traceable. Click the source link right under the headline figure (and in the Sources section) and you'll land on the exact document we pulled it from.
- Kept current. Each page shows the report year it's based on.
The rule is simple: if you see a number on HardWaterHQ, you can click straight through to where it came from. If we can't trace it, we don't publish it.
About us: HardWaterHQ is part of Gravison Group. Questions or a correction? Contact us.
Disclosure: some product links are affiliate links, which means we may earn a commission if you buy through them — at no extra cost to you. This never affects the data.