Check Your Water Hardness

Enter your ZIP code or city name to see your water hardness level, how it compares to the national average, and what treatment you may need.

Covering 200+ ZIP codes with city-level data, plus state averages for all 50 states.

How This Tool Works

1

Enter your ZIP code — we check it against our database of 200+ ZIP codes mapped to specific municipal water systems.

2

Get your hardness level — if we have city-level data, you'll see exact GPG/PPM values from official water quality reports. Otherwise, you'll see your state's average.

3

See your recommendation — based on your hardness level, we suggest the right type of treatment (or confirm you don't need any).

Water Hardness Scale

Soft0-1 GPG (0-17 PPM)
Slightly Hard1-3.5 GPG (17-60 PPM)
Moderately Hard3.5-7 GPG (60-120 PPM)
Hard7-10.5 GPG (120-180 PPM)
Very Hard10.5+ GPG (180+ PPM)
US Hardness Map
Interactive state-by-state
By State
All 50 states ranked
GPG/PPM Converter
Convert between units

Frequently Asked Questions

City-level data sourced from municipal Consumer Confidence Reports (CCRs). State averages from USGS and EPA SDWIS records. GPG values represent annual averages; actual hardness may vary by season and location.