Published April 5, 2026 · Updated monthly
Cities With the Worst Drinking Water in America
72 US water systems have active health-based violations under the Safe Drinking Water Act. These 20 systems have the lowest Water Safety Scores in our database — indicating serious, ongoing contamination issues that affect the safety of their drinking water.
Bottom 20 Water Systems
| Rank | Water System | State | Safety Score | Grade | Pop. Served |
|---|---|---|---|---|---|
| 1 | City of Jackson | MS | 0 | F | 189,673 |
| 2 | Newark Water Department | NJ | 5 | F | 294,274 |
| 3 | Tuscaloosa Water & Sewer | AL | 8 | F | 166,524 |
| 4 | Atlanta | GA | 10 | F | 1,089,893 |
| 5 | Shreveport Water System | LA | 10 | F | 192,378 |
| 6 | Mobile, Bd. Of W&s Comm. Of the City Of | AL | 16 | F | 279,000 |
| 7 | Bjw&sa (0720003) | SC | 16 | F | 145,634 |
| 8 | Papillion, City Of | NE | 32 | F | 35,000 |
| 9 | Gilbert, Town Of | AZ | 33 | F | 247,600 |
| 10 | Liberty Utilities New York - Lynbrook | NY | 34 | F | 220,000 |
| 11 | Kalamazoo | MI | 36 | F | 192,992 |
| 12 | Kearney, City Of | NE | 37 | F | 34,000 |
| 13 | Columbia City of (sc4010001) | SC | 38 | F | 319,500 |
| 14 | Columbus Public Water System | OH | 40 | F | 1,305,946 |
| 15 | Springfield Water and Sewer Commission | MA | 40 | F | 167,954 |
| 16 | Las Cruces Municipal Water System | NM | 40 | F | 98,175 |
| 17 | Sioux City Water Supply | IA | 40 | F | 85,791 |
| 18 | City of Baltimore | MD | 44 | F | 1,600,000 |
| 19 | Clermont Public Water System | OH | 45 | F | 133,059 |
| 20 | Fort Wayne - 3 Rivers Filtration Plant | IN | 50 | F | 269,994 |
Common Contaminants in Failing Systems
- Lead — Leaches from aging pipes and fixtures. The EPA action level is 15 ppb, but no amount of lead is safe. Flint, Michigan brought national attention to lead contamination, but many systems still exceed safe levels.
- Disinfection byproducts (THMs, HAAs) — Created when chlorine reacts with organic matter in water. Long-term exposure is linked to increased cancer risk.
- PFAS — "Forever chemicals" from industrial contamination. The EPA set new enforceable limits in 2024 at 4 ppt for PFOA and PFOS. Many systems exceed these levels.
- Arsenic — Naturally occurring in groundwater in many regions. The EPA limit is 10 ppb, but health effects occur at lower levels.
- Nitrate — From agricultural runoff. Particularly dangerous for infants (blue baby syndrome). EPA limit is 10 mg/L.
Why These Systems Fail
The worst water systems share common characteristics: aging infrastructure (many with pipes over 50 years old), underfunded utilities that cannot afford treatment upgrades, proximity to industrial or agricultural contamination sources, and in some cases, small system size that makes modern treatment economically unfeasible.
The American Society of Civil Engineers estimates the US needs $625 billion in drinking water infrastructure investment over the next 20 years. Without this investment, more systems will deteriorate.
If you live in an area served by one of these systems, see our guide to checking your water safety for steps you can take to protect your household.
Frequently Asked Questions
The water systems with the lowest Safety Scores are listed in the table above. Note that water quality varies by system, not just city — a single city may be served by multiple water systems with different quality levels.
Not necessarily. Bottled water is regulated by the FDA with standards similar to EPA tap water standards. Many bottled water brands are simply filtered municipal water. For most Americans, a home water filter provides better protection at lower cost than bottled water.
Reverse osmosis (RO) filters remove the widest range of contaminants, including lead, PFAS, arsenic, and most organic compounds. Activated carbon filters are effective for disinfection byproducts and organic chemicals but less effective for heavy metals. Choose a filter based on your specific contaminants.