How hard is your water?
Look up the mineral hardness your utility reports for your ZIP code, and see where the number comes from.
Enter your ZIP code to see what your water is carrying.
The four hardness tiers
Water above 7 grains per gallon is considered hard. Much of the Midwest, the Southwest, Florida and Southern California sits well above it.
Form I
Soft
0 to 3.5 grains per gallon
A light Part B dose, acting as little more than a finishing rinse.
Form II
Moderate
3.5 to 7 grains per gallon
A standard dose that stops slow mineral film and fabric stiffening.
Form III
Hard
7 to 10.5 grains per gallon
An active chelating dose to reverse visible haze and graying whites.
Form IV
Extreme
10.5+ grains per gallon
Full chelating strength, requiring a heavy dose to combat heavy scale.
Every tier receives the same pure, concentrated citric Part B. Your label gives the exact dose for your water.
Typical hardness by state
The median of the utility-reported values in each state. Cities within a state can differ widely, so check your own ZIP code above.
How we source each reading
Every result tells you where its number came from. We use the most direct source available for your ZIP code, in this order.
Checked against your utility
For many large cities we read the utility’s own water quality report and record its published hardness, with a link to the source.
Reported by your utility
Otherwise we use the hardness your city’s water system reports, or compute it from the calcium and magnesium it reports.
Nearby or regional
Where your city has no report, we use a neighboring utility within 15 km, then the median of USGS and EPA samples for your county.
Sources: the TapWaterData US Water Hardness Dataset (CC BY 4.0), which compiles utility Consumer Confidence Reports and the EPA/USGS Water Quality Portal; utility reports checked by Vetro; and ZIP code locations from GeoNames (CC BY 4.0). Utility values are system averages. Your tap can vary with season, blending and plumbing. If your reading looks wrong, write to [email protected].