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WATER SAFETY SCORE · 0–88
25 worst cities for tap water quality
Ranked by our Water Safety Score — the same 0–88 exposure profile used on each city report. Regulatory PFAS MCL violations weigh heaviest; monitoring detections and lead, DBP, and chromium flags in our profiles add smaller penalties. This is not your ZIP's live SDWIS compliance score.
Only tracked metros with WaterCheckup city guides (25 shown). For PFAS-only leaderboards see peak PFAS systems and PFAS MCL cities.
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San Antonio, TX
Grade D+ · 59/88
272 mg/L hardness · PFAS in UCMR5
San Antonio water quality · PFAS in San Antonio water · water contamination
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Gaithersburg, MD
Grade B · 74/88
WSSC Water · PFAS & testing context
Gaithersburg water quality · water testing Gaithersburg MD · WSSC tap water
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#1
Pensacola, FLGrade F
PFAS Above EPA Limit · 55K residents
34/88
#2
Fort Worth, TXGrade F
PFAS Above EPA Limit · 936K residents
39/88
#3
Sacramento, CAGrade F
PFAS Above EPA Limit · 524K residents
41/88
#4
Philadelphia, PAGrade F
PFAS Above EPA Limit · 1.6M residents
42/88
#5
Rochester, NYGrade F
PFAS Above EPA Limit · 210K residents
42/88
#6
Boise, IDGrade F
PFAS Above EPA Limit · 240K residents
43/88
#7
Fresno, CAGrade F
PFAS Above EPA Limit · 546K residents
43/88
#8
Miami, FLGrade F
PFAS Above EPA Limit · 2.8M residents
43/88
#9
Gilbert, AZGrade F
PFAS Above EPA Limit · 260K residents
44/88
#10
Madison, WIGrade F
PFAS Above EPA Limit · 270K residents
44/88
#11
Newark, NJGrade F
PFAS Above EPA Limit · 310K residents
45/88
#12
Anaheim, CAGrade F
PFAS Above EPA Limit · 350K residents
46/88
#13
Birmingham, ALGrade F
PFAS Above EPA Limit · 210K residents
48/88
#14
Grand Rapids, MIGrade F
PFAS Above EPA Limit · 195K residents
48/88
#15
Hartford, CTGrade F
PFAS Above EPA Limit · 125K residents
48/88
#16
Sugar Land, TXGrade F
PFAS Above EPA Limit · 91K residents
48/88
#17
Dallas, TXGrade F
PFAS Above EPA Limit · 1.3M residents
49/88
#18
Reno, NVGrade F
PFAS Above EPA Limit · 260K residents
49/88
#19
Fayetteville, NCGrade D-
PFAS Above EPA Limit · 210K residents
50/88
#20
Greensboro, NCGrade D-
PFAS Above EPA Limit · 290K residents
50/88
#21
Des Moines, IAGrade D-
PFAS Above EPA Limit · 215K residents
53/88
#22
Mesa, AZGrade D-
PFAS Detected · 500K residents
53/88
#23
Fairfax, VAGrade D
PFAS Above EPA Limit · 1.1M residents
54/88
#24
Glendale, CAGrade D
PFAS Above EPA Limit · 200K residents
54/88
#25
Parkersburg, WVGrade D
PFAS Above EPA Limit · 29K residents
55/88