Water hardness by ZIP code in the United States

Enter your ZIP code: we match it to the nearest city with published hardness data and show its value, unit and source.

How the search works

Every ZIP code is matched to the nearest of the 1372 cities in the United States for which a water supplier or regulator publishes hardness. Supply areas do not follow ZIP code boundaries, so the result is the figure of the nearest published supply. If the match is more than 15 km away we say so, and the annual water quality report of your own supplier is the better reference. Each city page names the source document and its date and, where the supplier publishes them, the values of each supply zone.

USGS classes: soft 0–60, moderately hard 61–120, hard 121–180, very hard >180 mg/L.

Regions

Largest cities in the United States

	gpg	mg/L
New York	1.9	32	soft
Los Angeles	7.5	128	hard
Chicago	7.9	135	hard
Houston	6.4	110	moderately hard
Phoenix	13.8	237	very hard
Philadelphia	8.9	152	hard
San Antonio	17.5	300	very hard
San Diego	14	240	very hard
Austin	5.4	93	moderately hard
Fort Worth	7.5	129	hard
San Jose	8.8	151	hard
Columbus	7.2	123	hard
Charlotte	1.9	32	soft
Indianapolis	18.5	317	very hard
San Francisco	3.6	62	moderately hard
Seattle	1.5	26	soft
Denver	6.1	105	moderately hard
El Paso	10.2	175	hard
Washington, D.C.	8.1	139	hard
Las Vegas	16.4	280	very hard
Boston	0.8	13	soft
Detroit	6.3	107	moderately hard
Portland	2.6	45	soft
Louisville	7.5	128	hard
Memphis	2.8	48	soft
Baltimore	5.5	95	moderately hard
Albuquerque	9.1	155	hard
Milwaukee	7.6	130	hard
Fresno	5.2	89	moderately hard
Tucson	13.4	229	very hard
Sacramento	2.8	49	soft
Mesa	16	274	very hard
Omaha	9	154	hard
Raleigh	1.5	25	soft
Long Beach	8.6	148	hard
Virginia Beach	3.6	61	moderately hard
Oakland	1.6	27	soft
Minneapolis	5.4	93	moderately hard
Tulsa	6.7	115	moderately hard
Aurora	7.9	136	hard

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