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These cities have the lowest scores on EPA's own records: health-based violations, Lead and Copper Rule results, UCMR5 PFAS monitoring and 2012–2019 compliance samples. Browse by overall score or by specific contaminant to see if your city is affected.
Water contamination is a serious public health concern affecting millions of Americans. If your city appears on these lists, consider testing your home water and using a certified filter appropriate for your specific contaminants.
You can't change your city's source water, but you can control what comes out of your own tap. Start by finding out what's actually in it — municipal reports don't capture the lead your home's plumbing can add — then match a filter to the result. The contaminants that land a city on these rankings (lead, arsenic, nitrate, PFAS) are exactly the ones a basic carbon pitcher does not remove; that takes reverse osmosis.
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See which cities have the highest levels of each contaminant. Click any contaminant to view the top 100 most affected cities.
Cities ranked by overall EPA-record score (rubric v2 — see the methodology). Lower scores mean more health-based violations, higher lead results, PFAS above the federal limit or historical readings near an MCL. Cities we cannot match to an EPA system are excluded.
| Rank | City | State | Score | Grade | Why (EPA findings) | Population |
|---|---|---|---|---|---|---|
| #1 | Lauderhill | Florida | 21/100 | F | 4 health-based violations (MCL/treatment-technique) in the l…33 monitoring/reporting violations in the last 5 years | 55,000 |
| #2 | Syracuse | New York | 29/100 | F | 10 health-based violations (MCL/treatment-technique) in the …1 health-based violation still unresolved with EPA/state | 192,000 |
| #3 | Valdosta | Georgia | 33/100 | F | 6 health-based violations (MCL/treatment-technique) in the l…1 monitoring/reporting violation in the last 5 years | 48,959 |
| #4 | Yucaipa | California | 34/100 | F | 3 health-based violations (MCL/treatment-technique) in the l…1 health-based violation still unresolved with EPA/state | 52,010 |
| #5 | Hallandale Beach | Florida | 34/100 | F | 1 health-based violation (MCL/treatment-technique) in the la…1 health-based violation still unresolved with EPA/state | 40,000 |
| #6 | Dania Beach | Florida | 34/100 | F | 1 health-based violation (MCL/treatment-technique) in the la…1 health-based violation still unresolved with EPA/state | 30,000 |
| #7 | Porterville | California | 43/100 | F | 1 health-based violation (MCL/treatment-technique) in the la…1 health-based violation still unresolved with EPA/state | 63,487 |
| #8 | Bullhead City | Arizona | 44/100 | F | 2 health-based violations (MCL/treatment-technique) in the l…142 monitoring/reporting violations in the last 5 years | 36,330 |
| #9 | Prescott | Arizona | 51/100 | F | 1 health-based violation (MCL/treatment-technique) in the la…36 monitoring/reporting violations in the last 5 years | 42,217 |
| #10 | Prichard | Alabama | 52/100 | F | 8 health-based violations (MCL/treatment-technique) in the l…8 monitoring/reporting violations in the last 5 years | 29,190 |
| #11 | Yuma | Arizona | 53/100 | F | 7 health-based violations (MCL/treatment-technique) in the l…7 monitoring/reporting violations in the last 5 years | 103,264 |
| #12 | Pembroke Pines | Florida | 54/100 | F | 1 health-based violation (MCL/treatment-technique) in the la…40 monitoring/reporting violations in the last 5 years | 187,459 |
| #13 | Palm Bay | Florida | 54/100 | F | 2 health-based violations (MCL/treatment-technique) in the l…PFOA detected at up to 8.5 ppt in UCMR5 sampling (2024-12-11… | 140,750 |
| #14 | Goodyear | Arizona | 54/100 | F | 34 monitoring/reporting violations in the last 5 yearsPFOA detected at up to 4.8 ppt in UCMR5 sampling (2024-06-07… | 50,001 |
| #15 | Riviera Beach | Florida | 54/100 | F | 1 health-based violation (MCL/treatment-technique) in the la…12 monitoring/reporting violations in the last 5 years | 46,762 |
| #16 | Union City | Georgia | 54/100 | F | 5 health-based violations (MCL/treatment-technique) in the l…Other PFAS detected in UCMR5 sampling: PFBS 3.4 ppt, PFPeA 3… | 18,636 |
| #17 | Calumet City | Illinois | 55/100 | F | 1 health-based violation (MCL/treatment-technique) in the la…1 health-based violation still unresolved with EPA/state | 37,000 |
| #18 | Junction City | Kansas | 55/100 | F | 5 health-based violations (MCL/treatment-technique) in the l…5 monitoring/reporting violations in the last 5 years | 19,167 |
| #19 | Stockton | California | 56/100 | F | 2 health-based violations (MCL/treatment-technique) in the l…2 monitoring/reporting violations in the last 5 years | 191,302 |
| #20 | Shreveport | Louisiana | 57/100 | F | 20 health-based violations (MCL/treatment-technique) in the …1 monitoring/reporting violation in the last 5 years | 192,378 |
| #21 | Medford | Massachusetts | 57/100 | F | 2 health-based violations (MCL/treatment-technique) in the l…1 health-based violation still unresolved with EPA/state | 61,700 |
| #22 | San Luis | Arizona | 57/100 | F | 2 health-based violations (MCL/treatment-technique) in the l…1 health-based violation still unresolved with EPA/state | 39,705 |
| #23 | New Orleans | Louisiana | 58/100 | F | 1 health-based violation (MCL/treatment-technique) in the la…3 monitoring/reporting violations in the last 5 years | 334,903 |
| #24 | Monroe | Louisiana | 58/100 | F | 4 health-based violations (MCL/treatment-technique) in the l…Other PFAS detected in UCMR5 sampling: PFBA 8.2 ppt | 57,000 |
| #25 | Andover | Massachusetts | 58/100 | F | 2 health-based violations (MCL/treatment-technique) in the l…1 health-based violation still unresolved with EPA/state | 36,569 |
| #26 | Lawrence | Indiana | 59/100 | F | 4 health-based violations (MCL/treatment-technique) in the l…1 monitoring/reporting violation in the last 5 years | 49,000 |
| #27 | Opelousas | Louisiana | 60/100 | D | 6 health-based violations (MCL/treatment-technique) in the l… | 20,388 |
| #28 | Gilbert | Arizona | 61/100 | D | 79 monitoring/reporting violations in the last 5 yearsPFOA detected at up to 6.5 ppt in UCMR5 sampling (2024-11-05… | 247,600 |
| #29 | Modesto | California | 61/100 | D | Lead 90th-percentile tap result 12 ppb for 2025-01-01–2027-1…PFOA detected at up to 8.6 ppt in UCMR5 sampling (2024-09-12… | 218,771 |
| #30 | Joliet | Illinois | 61/100 | D | 1 health-based violation (MCL/treatment-technique) in the la…6 monitoring/reporting violations in the last 5 years | 160,000 |
| #31 | Miami Beach | Florida | 61/100 | D | 14 monitoring/reporting violations in the last 5 yearsLead 90th-percentile tap result 7 ppb for 2025-01-01–2025-12… | 100,000 |
| #32 | Pinellas Park | Florida | 61/100 | D | 3 health-based violations (MCL/treatment-technique) in the l…5 monitoring/reporting violations in the last 5 years | 48,939 |
| #33 | Alabaster | Alabama | 61/100 | D | 1 health-based violation (MCL/treatment-technique) in the la…3 monitoring/reporting violations in the last 5 years | 40,986 |
| #34 | West Palm Beach | Florida | 62/100 | D | 3 health-based violations (MCL/treatment-technique) in the l…2 monitoring/reporting violations in the last 5 years | 132,000 |
| #35 | Elgin | Illinois | 63/100 | D | 6 monitoring/reporting violations in the last 5 yearsLead 90th-percentile tap result 53 ppb for 2025-07-01–2025-1… | 114,797 |
| #36 | Winter Haven | Florida | 63/100 | D | 22 monitoring/reporting violations in the last 5 yearsLead 90th-percentile tap result 7 ppb for 2023-01-01–2023-12… | 87,537 |
| #37 | Hialeah | Florida | 64/100 | D | 15 monitoring/reporting violations in the last 5 yearsPFOA detected at up to 10.2 ppt in UCMR5 sampling (2024-08-2… | 238,000 |
| #38 | Fort Lauderdale | Florida | 64/100 | D | 81 monitoring/reporting violations in the last 5 yearsPFOA detected at up to 4.9 ppt in UCMR5 sampling (2023-11-01… | 185,163 |
| #39 | Ontario | California | 64/100 | D | PFOA detected at up to 30 ppt in UCMR5 sampling (2024-02-28)…PFOS detected at up to 5.2 ppt in UCMR5 sampling (2024-02-28… | 185,010 |
| #40 | Hollywood | Florida | 64/100 | D | 45 monitoring/reporting violations in the last 5 yearsPFOA detected at up to 6 ppt in UCMR5 sampling (2024-03-07),… | 147,566 |
| #41 | Pompano Beach | Florida | 64/100 | D | 25 monitoring/reporting violations in the last 5 yearsPFOA detected at up to 6.6 ppt in UCMR5 sampling (2023-07-17… | 99,400 |
| #42 | North Miami | Florida | 64/100 | D | 15 monitoring/reporting violations in the last 5 yearsPFOA detected at up to 12 ppt in UCMR5 sampling (2024-01-29)… | 89,349 |
| #43 | Naples | Florida | 64/100 | D | 14 monitoring/reporting violations in the last 5 yearsPFOA detected at up to 4.2 ppt in UCMR5 sampling (2023-12-06… | 83,804 |
| #44 | Sunrise | Florida | 64/100 | D | 25 monitoring/reporting violations in the last 5 yearsPFOA detected at up to 4.9 ppt in UCMR5 sampling (2024-02-05… | 79,550 |
| #45 | Coral Springs | Florida | 64/100 | D | 16 monitoring/reporting violations in the last 5 yearsPFOA detected at up to 5 ppt in UCMR5 sampling (2025-06-05),… | 65,000 |
| #46 | Tamarac | Florida | 64/100 | D | 28 monitoring/reporting violations in the last 5 yearsPFOA detected at up to 5.7 ppt in UCMR5 sampling (2025-07-24… | 63,793 |
| #47 | Margate | Florida | 64/100 | D | 35 monitoring/reporting violations in the last 5 yearsPFOA detected at up to 6.5 ppt in UCMR5 sampling (2024-08-20… | 62,254 |
| #48 | Gilroy | California | 64/100 | D | 1 health-based violation (MCL/treatment-technique) in the la…PFOA detected at up to 8 ppt in UCMR5 sampling (2025-06-25),… | 59,203 |
| #49 | Fort Pierce | Florida | 64/100 | D | 13 monitoring/reporting violations in the last 5 yearsPFOA detected at up to 4.5 ppt in UCMR5 sampling (2023-07-26… | 58,000 |
| #50 | Brighton | Colorado | 64/100 | D | 1 health-based violation (MCL/treatment-technique) in the la…PFOA detected at up to 5.3 ppt in UCMR5 sampling (2025-08-19… | 56,304 |
Our water quality scores (0-100) are calculated based on three factors:
Being on this list doesn't mean water is unsafe to drink, but indicates:
Click on your city in the rankings or use our search to see exactly which contaminants are present and at what levels.
Not all filters remove all contaminants. Choose a filter certified to remove the specific contaminants found in your water.
Municipal testing doesn't capture contaminants from your home plumbing. Testing your tap water directly provides the most relevant data.
Request your utility's annual Consumer Confidence Report and stay aware of any water quality advisories in your area.