Skip to main content
💧 TapWaterData

Water Hardness in Arizona

Across 54 measured cities — with 99 more covered by labeled county-level estimates — Arizona's median tap water hardness is 168.3 mg/L (9.8 gpg): hard on the USGS scale. Below: every covered city, the state's hardest and softest water, and the geology that explains it.

Data updated July 6, 2026. Sources: utility-reported water quality data and USGS/EPA Water Quality Portal samples.

State Median
168.3
mg/L (9.8 gpg), measured cities
Measured Range
64.3-535.0
mg/L across measured cities
Measured Cities
54
utility-reported or computed values
County Estimates
99
65% of covered cities

Arizona Cities by Hardness Category

Measured cities only — labeled county estimates never enter the category counts or the median.

CategoryRangeMeasured citiesShare
Soft0-60 mg/L00.0%
Moderately hard60-120 mg/L1527.8%
Hard120-180 mg/L3666.7%
Very hard>180 mg/L35.6%

Hardest and Softest Water in Arizona

Measured values only; labeled county estimates and values under active dispute never rank.

Hardest water in Arizona

  1. Patagonia — 535.0 mg/L (31.3 gpg), very hard
  2. Eloy — 343.0 mg/L (20.1 gpg), very hard
  3. Phoenix — 237.0 mg/L (13.9 gpg), very hard
  4. Catalina Foothills — 180.0 mg/L (10.5 gpg), hard
  5. Drexel Heights — 180.0 mg/L (10.5 gpg), hard

Softest water in Arizona

  1. Apache Junction — 64.3 mg/L (3.8 gpg), moderately hard
  2. Gold Canyon — 64.3 mg/L (3.8 gpg), moderately hard
  3. Queen Valley — 64.3 mg/L (3.8 gpg), moderately hard
  4. Elephant Head — 67.4 mg/L (3.9 gpg), moderately hard
  5. Green Valley — 67.4 mg/L (3.9 gpg), moderately hard

Every Covered City in Arizona

All 153 covered Arizona cities, sorted by population served. "County estimate" rows are labeled context values from USGS/EPA Water Quality Portal county sampling — they never enter the median above. City names link to each city's full water quality page.

CityHardness (mg/L)gpgCategoryData
Glendale168.59.8HardUtility-reported
Peoria167.99.8HardUtility-reported
Guadalupe171.810.1HardUtility-reported
Paradise Valley170.910.0HardUtility-reported
Cave Creek171.210.0HardUtility-reported
New River171.210.0HardUtility-reported
Phoenix237.013.9Very hardUtility-reported
Anthem171.010.0HardUtility-reported
Flowing Wells179.510.5HardUtility-reported
Casas Adobes179.510.5HardUtility-reported
Oro Valley179.510.5HardUtility-reported
Marana180.010.5HardUtility-reported
Tucson180.010.5HardUtility-reported
Tucson Mountains180.010.5HardUtility-reported
Catalina Foothills180.010.5HardUtility-reported
Drexel Heights180.010.5HardUtility-reported
South Tucson180.010.5HardUtility-reported
Tanque Verde180.010.5HardUtility-reported
Three Points180.010.5HardUtility-reported
Tucson Estates180.010.5HardUtility-reported
Valencia West180.010.5HardUtility-reported
Mesa140.88.2HardUtility-reported
Carefree175.010.2HardUtility-reported
Chandler139.08.1HardUtility-reported
Gilbert168.09.8HardUtility-reported
Scottsdale172.010.1HardUtility-reported
Goodyear153.59.0HardUtility-reported
Tempe180.010.5HardUtility-reported
Surprise134.57.9HardUtility-reported
Avondale105.06.1Moderately hardUtility-reported
Eloy343.020.1Very hardUtility-reported
Florence109.06.4Moderately hardUtility-reported
Yuma383.022.4Very hardCounty estimate
Coolidge220.012.9Very hardCounty estimate
Casa Grande220.012.9Very hardCounty estimate
Arizona City220.012.9Very hardCounty estimate
Buckeye141.08.3HardUtility-reported
Prescott Valley109.16.4Moderately hardUtility-reported
Queen Creek178.010.4HardUtility-reported
San Tan Valley109.06.4Moderately hardUtility-reported
Citrus Park141.08.3HardUtility-reported
Flagstaff161.09.4HardUtility-reported
Apache Junction64.33.8Moderately hardUtility-reported
Gold Canyon64.33.8Moderately hardUtility-reported
Queen Valley64.33.8Moderately hardUtility-reported
Lake Havasu City284.016.6Very hardCounty estimate
Sierra Vista170.09.9HardCounty estimate
Maricopa220.012.9Very hardCounty estimate
Sahuarita207.012.1Very hardCounty estimate
Litchfield Park105.06.1Moderately hardUtility-reported
El Mirage208.012.2Very hardCounty estimate
Green Valley67.43.9Moderately hardUtility-reported
Prescott104.06.1Moderately hardUtility-reported
Youngtown75.14.4Moderately hardUtility-reported
Sun City West208.012.2Very hardCounty estimate
Sun City75.14.4Moderately hardUtility-reported
Fountain Hills90.05.3Moderately hardUtility-reported
Fortuna Foothills160.09.4HardUtility-reported
Sacaton220.012.9Very hardCounty estimate
Nogales220.012.9Very hardCounty estimate
Safford176.010.3HardCounty estimate
Thatcher176.010.3HardCounty estimate
Central176.010.3HardCounty estimate
Sun Lakes103.06.0Moderately hardUtility-reported
Fort Mohave284.016.6Very hardCounty estimate
Somerton383.022.4Very hardCounty estimate
Dragoon170.09.9HardCounty estimate
Payson255.014.9Very hardCounty estimate
Bullhead City284.016.6Very hardCounty estimate
Rio Rico220.012.9Very hardCounty estimate
Show Low139.58.2HardCounty estimate
Douglas170.09.9HardCounty estimate
Vail158.09.2HardUtility-reported
Whiteriver255.014.9Very hardCounty estimate
Cottonwood179.010.5HardUtility-reported
Bisbee170.09.9HardCounty estimate
Mammoth220.012.9Very hardCounty estimate
Pinetop139.58.2HardCounty estimate
Winslow139.58.2HardCounty estimate
Mohave Valley284.016.6Very hardCounty estimate
Elephant Head67.43.9Moderately hardUtility-reported
Tolleson208.012.2Very hardCounty estimate
Benson170.09.9HardCounty estimate
Clifton150.08.8HardCounty estimate
Morenci150.08.8HardCounty estimate
Holbrook139.58.2HardCounty estimate
Oracle220.012.9Very hardCounty estimate
Eagar69.04.0Moderately hardCounty estimate
Clarkdale151.08.8HardUtility-reported
St. Johns69.04.0Moderately hardCounty estimate
San Luis383.022.4Very hardCounty estimate
Pima176.010.3HardCounty estimate
Saint Johns69.04.0Moderately hardCounty estimate
Willcox176.010.3HardCounty estimate
Tubac220.012.9Very hardCounty estimate
Bagdad210.012.3Very hardCounty estimate
Williams237.013.9Very hardCounty estimate
Parker180.010.5HardCounty estimate
Wellton383.022.4Very hardCounty estimate
Quartzsite180.010.5HardCounty estimate
Chino Valley210.012.3Very hardCounty estimate
White Mountain Lake139.58.2HardCounty estimate
Dolan Springs284.016.6Very hardCounty estimate
Ash Fork237.013.9Very hardCounty estimate
Cameron237.013.9Very hardCounty estimate
Peach Springs284.016.6Very hardCounty estimate
Springerville69.04.0Moderately hardCounty estimate
Kearny220.012.9Very hardCounty estimate
Gila Bend208.012.2Very hardCounty estimate
Congress210.012.3Very hardCounty estimate
Ajo207.012.1Very hardCounty estimate
Second Mesa139.58.2HardCounty estimate
Huachuca City170.09.9HardCounty estimate
Tuba City237.013.9Very hardCounty estimate
Paulden210.012.3Very hardCounty estimate
Joseph City139.58.2HardCounty estimate
Many Farms69.04.0Moderately hardCounty estimate
Topock284.016.6Very hardCounty estimate
St. David170.09.9HardCounty estimate
Mayer210.012.3Very hardCounty estimate
Saint David170.09.9HardCounty estimate
Colorado City284.016.6Very hardCounty estimate
Heber139.58.2HardCounty estimate
Hotevilla237.013.9Very hardCounty estimate
Littlefield284.016.6Very hardCounty estimate
Pomerene170.09.9HardCounty estimate
Pinedale139.58.2HardCounty estimate
Supai237.013.9Very hardCounty estimate
Fort Defiance69.04.0Moderately hardCounty estimate
Patagonia535.031.3Very hardUtility-reported
Lakeside139.58.2HardCounty estimate
Stanfield220.012.9Very hardCounty estimate
Yarnell210.012.3Very hardCounty estimate
Kingman284.016.6Very hardCounty estimate
Fredonia237.013.9Very hardCounty estimate
Taylor139.58.2HardCounty estimate
Grand Canyon237.013.9Very hardCounty estimate
Eden176.010.3HardCounty estimate
Pine255.014.9Very hardCounty estimate
Tombstone170.09.9HardCounty estimate
Mormon Lake237.013.9Very hardCounty estimate
Picacho220.012.9Very hardCounty estimate
Bouse180.010.5HardCounty estimate
Leupp237.013.9Very hardCounty estimate
Rillito207.012.1Very hardCounty estimate
Vernon69.04.0Moderately hardCounty estimate
Higley208.012.2Very hardCounty estimate
Pearce170.09.9HardCounty estimate
Alpine69.04.0Moderately hardCounty estimate
Ehrenberg180.010.5HardCounty estimate
Happy Jack237.013.9Very hardCounty estimate
Humboldt210.012.3Very hardCounty estimate
Keams Canyon139.58.2HardCounty estimate

Above 120 mg/L (7 gpg), scale is usually worth treating — see our water softener guide, or size a system with the hardness calculator & converter.

The Geology Behind Arizona's Water Hardness

Arizona sits in the Mountain West basins and desert Southwest region.

Mountain snowmelt starts out soft, but across the interior West it drains into closed basins floored with carbonate and evaporite sediments, and the arid climate evaporates water faster than rain can dilute it. Rivers like the Colorado accumulate dissolved calcium and magnesium along their whole length, so the USGS maps most basin-and-range and desert-Southwest supplies as hard to very hard. Towns high in the mountains that capture snowmelt directly are the region's soft-water exceptions.

Source: USGS Water Science School - Hardness of Water

Arizona Water Hardness FAQ

Does Arizona have hard water?

Yes — across Arizona's measured cities, typical tap water is hard. The median is 168.3 mg/L (9.8 gpg) — hard on the USGS scale, where anything above 120 mg/L (7 gpg) counts as hard. 39 of Arizona's 54 measured cities fall in the hard or very hard bands (72%), so check your own city rather than the state average.

How hard is tap water in Arizona?

Across the 54 Arizona cities with measured values in our index, the median hardness is 168.3 mg/L (9.8 gpg) — hard on the USGS scale. Individual cities range from 64.3 to 535.0 mg/L, so check your own city rather than assuming the state number.

Which city in Arizona has the hardest water?

Patagonia has the hardest measured tap water in our Arizona index at 535.0 mg/L (31.3 gpg) — very hard on the USGS scale. Rankings use measured utility values only; labeled county estimates and values under active dispute are excluded.

Do I need a water softener in Arizona?

39 of Arizona's 54 measured cities (72%) fall in the hard or very hard bands — above 120 mg/L (7 gpg), the level where most water treatment professionals suggest considering an ion-exchange softener. Hardness varies utility to utility, so look up your own city's value before sizing equipment.

How do I find my city's exact water hardness?

Enter your ZIP code in our free lookup at tapwaterdata.com/zip to see the value we hold for your Arizona city from utility-reported water quality data, check your water utility's annual Consumer Confidence Report (CCR), or use a home test-strip kit.

← Water hardness across the USInteractive hardness mapCalculator & converterFree ZIP-code hardness lookupData & methodology

By TapWaterData Editorial

Stay Informed About Your Water Quality

Get EPA reports, filter recommendations, and safety alerts for your area.

Join 10,000+ people protecting their families. Unsubscribe anytime.