Arizona water quality
Arizona has 1,637 active public water systems (4,255 on file total), 908 of them graded by TapGraded.
Grade distribution
Biggest water systems
MESA CITY OF
MESA, AZ · 466,000 served
GILBERT, TOWN OF
GILBERT, AZ · 247,600 served
CHANDLER CITY OF
CHANDLER, AZ · 247,328 served
SCOTTSDALE CITY OF
SCOTTSDALE, AZ · 241,361 served
GLENDALE CITY OF
PHOENIX, AZ · 234,766 served
PEORIA CITY OF
PEORIA, AZ · 187,676 served
TEMPE CITY OF
TEMPE, AZ · 165,000 served
ARIZONA WATER CO - PINAL VALLEY
PHOENIX, AZ · 134,432 served
EPCOR - AGUA FRIA
EL MIRAGE, AZ · 127,718 served
CITY OF YUMA
YUMA, AZ · 103,264 served
Lowest-graded systems
Active, graded systems serving at least 10,000 people, ordered by lowest Tap Grade first.
WMATUA Miner Flat
Whiteriver, AZ · 15,570 served
CITY OF YUMA
YUMA, AZ · 103,264 served
GRAND CANYON NATIONAL PARK
GRAND CANYON, AZ · 16,590 served
SAN LUIS CITY OF
SAN LUIS, AZ · 39,705 served
BULLHEAD CITY MOHAVE
BULLHEAD CITY, AZ · 36,330 served
EPCOR - AGUA FRIA
EL MIRAGE, AZ · 127,718 served
PIMA UTILITIES
PHOENIX, AZ · 20,000 served
PRESCOTT CITY OF
PRESCOTT, AZ · 42,217 served
FLOWING WELLS IRRIGATION DISTRICT
TUCSON, AZ · 16,000 served
ARIZONA WATER CO - SEDONA
PHOENIX, AZ · 12,104 served
Cities in Arizona
Source: EPA SDWIS/ECHO · Data as of 2026Q2