Free tap water grades for 1,100+ water systems & 10,000+ ZIP codesFree tap water grades for 10,000+ ZIP codes Official EPA compliance records · Independent ratings

Colorado Water Quality Ratings

TapWaterSafety has rated 27 public water systems in Colorado, serving a combined 6,183,574 residents. The statewide average grade is C.

Data sources: EPA SDWIS EPA ECHO EWG Tap Water Database Utility CCRs ⓘ How did we get these ratings?
State average grade
C
70/100
Total utilities rated 27
Population served 6,183,574
Most recent test 2024

Top water quality concerns in Colorado

  • Haloacetic acids (HAA9) significantly above health guideline
  • Total trihalomethanes (TTHMs) significantly above health guideline
  • Haloacetic acids (HAA5) significantly above health guideline
  • PFAS contamination
  • Perfluorohexane sulfonate (PFHXS) significantly above health guideline

Cities in Colorado

Browse tap water quality reports by city. Click any city to see its grade, what's in the water, and recommended filters.

ARVADA
C 171,610
Aurora
F 599,537
BOULDER
C 166,080
BRIGHTON
F 56,304
BROOMFIELD
C 106,153
CASTLE ROCK
C 106,822
CENTENNIAL
C 55,000
COMMERCE CITY
D 75,559
Colorado Springs
C 464,111
Denver
C 1,287,000
ENGLEWOOD
F 57,332
FORT COLLINS
C 243,433
GRAND JUNCTION
C 92,580
GREELEY
C 132,310
HIGHLANDS RANCH
D 103,444
LAKEWOOD
D 81,400
LONGMONT
B 102,866
LOVELAND
C 95,471
PARKER
D 75,949
PUEBLO
B 114,070
THORNTON
F 226,465
WESTMINSTER
C 202,078

Grade distribution

A
2 (7%)
B
9 (33%)
C
8 (30%)
D
4 (15%)
F
4 (15%)

All rated utilities in Colorado

Sorted by score, highest first. Click any utility to see the full grade card.

Rank Utility City Population Score Grade
#1 PUEBLO BOARD OF WW PUEBLO 114,070 87 A
#2 Colorado Springs Water Utilities Colorado Springs 478,000 86 A
#3 LONGMONT CITY OF LONGMONT 102,866 82 B
#4 FT COLLINS LOVELAND WD FORT COLLINS 63,532 80 B
#5 BOULDER CITY OF BOULDER 166,080 79 B
#6 UTE WCD GRAND JUNCTION 92,580 79 B
#7 SOUTHGATE WSD CENTENNIAL 55,000 78 B
#8 COLORADO SPRINGS UTILITIES COLORADO SPRINGS 464,111 78 B
#9 LOVELAND CITY OF LOVELAND 95,471 78 B
#10 Aurora Water Utilities Aurora 374,000 78 B
#11 CASTLE ROCK TOWN OF CASTLE ROCK 106,822 75 B
#12 WESTMINSTER CITY OF WESTMINSTER 202,078 74 C
#13 GREELEY CITY OF GREELEY 132,310 74 C
#14 Denver Municipal Water System Denver 716,000 74 C
#15 BROOMFIELD CITY AND COUNTY OF BROOMFIELD 106,153 73 C
#16 DENVER WATER BOARD DENVER 1,287,000 73 C
#17 ARVADA CITY OF ARVADA 171,610 72 C
#18 FT COLLINS CITY OF FORT COLLINS 179,901 68 C
#19 HIGHLANDS RANCH WSD HIGHLANDS RANCH 103,444 66 C
#20 SOUTH ADAMS COUNTY WSD COMMERCE CITY 75,559 62 D
#21 CONSOLIDATED MUTUAL MAPLE GROVE LAKEWOOD 81,400 62 D
#22 PARKER WSD PARKER 75,949 60 D
#23 AURORA CITY OF AURORA 533,407 58 D
#24 EAST CHERRY CREEK VALLEY WSD AURORA 66,130 49 F
#25 ENGLEWOOD CITY OF ENGLEWOOD 57,332 49 F
#26 BRIGHTON CITY OF BRIGHTON 56,304 47 F
#27 THORNTON CITY OF THORNTON 226,465 44 F