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These cities have significant water quality challenges based on EPA contaminant data, compliance violations, and infrastructure concerns. Residents in these areas should strongly consider using certified water filters.
If your city appears on this list, we strongly recommend using a certified water filter to protect your family's health. Pay special attention to the specific contaminants found in your city's water.
View Filter RecommendationsClick any city to see detailed water quality report including specific contaminants, violations, and recommended filters.
| Rank | City | State | Score | Grade | Population Affected |
|---|---|---|---|---|---|
| #1 | Alameda | California | 44/100 | F | 79,827 |
| #2 | Union City | Georgia | 44/100 | F | 22,329 |
| #3 | San Bernardino | California | 45/100 | F | 222,101 |
| #4 | San Marcos | California | 45/100 | F | 97,477 |
| #5 | Windsor | Colorado | 45/100 | F | 32,551 |
| #6 | Mishawaka | Indiana | 46/100 | F | 51,063 |
| #7 | Bardstown | Kentucky | 46/100 | F | 13,567 |
| #8 | Indio | California | 47/100 | F | 92,301 |
| #9 | San Jose | California | 47/100 | F | 1,013,240 |
| #10 | Safety Harbor | Florida | 47/100 | F | 17,203 |
| #11 | Hanover Park | Illinois | 47/100 | F | 38,510 |
| #12 | Cape Coral | Florida | 48/100 | F | 194,016 |
| #13 | Plantation | Florida | 48/100 | F | 94,366 |
| #14 | Dalton | Georgia | 48/100 | F | 34,417 |
| #15 | Lenexa | Kansas | 48/100 | F | 57,434 |
| #16 | San Buenaventura | California | 49/100 | F | 110,763 |
| #17 | Arvada | Colorado | 49/100 | F | 124,402 |
| #18 | Wheat Ridge | Colorado | 49/100 | F | 32,133 |
| #19 | Jacksonville | Florida | 49/100 | F | 949,611 |
| #20 | Woodland | California | 50/100 | D | 61,032 |
| #21 | Peachtree City | Georgia | 50/100 | D | 38,633 |
| #22 | Hagerstown | Maryland | 50/100 | D | 43,527 |
| #23 | Nogales | Arizona | 51/100 | D | 20,103 |
| #24 | Durango | Colorado | 51/100 | D | 19,399 |
| #25 | Coral Springs | Florida | 51/100 | D | 133,759 |
| #26 | Parkland | Florida | 51/100 | D | 34,670 |
| #27 | Oswego | Illinois | 51/100 | D | 34,485 |
| #28 | Scottsdale | Arizona | 52/100 | D | 241,361 |
| #29 | Santa Clara | California | 52/100 | D | 127,134 |
| #30 | Houma | Louisiana | 52/100 | D | 33,727 |
| #31 | Parker | Colorado | 53/100 | D | 58,512 |
| #32 | Belleville | Illinois | 53/100 | D | 41,097 |
| #33 | Palatine | Illinois | 53/100 | D | 69,350 |
| #34 | Garden Grove | California | 54/100 | D | 172,800 |
| #35 | Alexandria | Louisiana | 54/100 | D | 45,275 |
| #36 | Quincy | Massachusetts | 54/100 | D | 101,636 |
| #37 | El Mirage | Arizona | 55/100 | C- | 35,753 |
| #38 | Palm Bay | Florida | 55/100 | C- | 119,760 |
| #39 | Aurora | Illinois | 55/100 | C- | 177,564 |
| #40 | Germantown | Maryland | 55/100 | C- | 91,249 |
| #41 | Kenai | Alaska | 56/100 | C- | 7,424 |
| #42 | Paradise Valley | Arizona | 56/100 | C- | 14,502 |
| #43 | Encinitas | California | 56/100 | C- | 62,671 |
| #44 | Mission Viejo | California | 56/100 | C- | 95,638 |
| #45 | North Miami | Florida | 56/100 | C- | 62,468 |
| #46 | St. Petersburg | Florida | 56/100 | C- | 258,308 |
| #47 | Baton Rouge | Louisiana | 56/100 | C- | 227,470 |
| #48 | Lake Charles | Louisiana | 56/100 | C- | 84,872 |
| #49 | Prescott | Arizona | 57/100 | C- | 43,376 |
| #50 | Pooler | Georgia | 57/100 | C- | 25,711 |
Contaminants like lead, arsenic, nitrates, or disinfection byproducts found at levels approaching or exceeding EPA maximum limits.
Multiple or recent violations of Safe Drinking Water Act requirements, including health-based violations or failure to properly monitor.
Old pipes, outdated treatment facilities, or inadequate distribution systems that contribute to water quality degradation.
Contamination from agricultural runoff, industrial discharge, or naturally occurring minerals in the source water supply.
Click on your city above to see the specific contaminants and violations affecting your water. Understanding the exact issues is the first step to protection.
Choose a filter certified to remove the specific contaminants in your water. Not all filters remove all contaminants. Look for NSF certification for your concerns.
Municipal testing doesn't include your home plumbing. Home tests can identify lead from pipes or other issues specific to your residence.
Review your water utility's annual Consumer Confidence Report. Attend public meetings about water quality and advocate for infrastructure improvements.