We analyzed tap water quality data for hundreds of cities in Louisiana to identify the 25 with the most contaminants exceeding health guidelines. This ranking is based on 2026 data from the EPA and EWG databases.
While all public water systems must meet EPA legal limits, many health experts — including the Environmental Working Group — argue that these legal limits are outdated and don't reflect current scientific understanding of safe exposure levels. The cities below have the widest gap between what's in their water and what's considered safe by modern health standards.
Rankings at a Glance
New Orleans, Louisiana
New Orleans has 15 contaminants exceeding EWG health guidelines out of 34 detected — significantly above the national average. Multiple known carcinogens were found at levels of concern.
See full New Orleans water report →Napoleonville, Louisiana
Napoleonville has 15 contaminants exceeding EWG health guidelines out of 31 detected — significantly above the national average. Multiple known carcinogens were found at levels of concern.
See full Napoleonville water report →Abbeville, Louisiana
Abbeville has 15 contaminants exceeding EWG health guidelines out of 23 detected — significantly above the national average. Multiple known carcinogens were found at levels of concern.
See full Abbeville water report →Rayville, Louisiana
Rayville has 15 contaminants exceeding EWG health guidelines out of 20 detected — significantly above the national average. Multiple known carcinogens were found at levels of concern.
See full Rayville water report →Belle Chasse, Louisiana
Belle Chasse has 14 contaminants exceeding EWG health guidelines out of 33 detected — significantly above the national average. Multiple known carcinogens were found at levels of concern.
See full Belle Chasse water report →Westwego, Louisiana
Westwego has 14 contaminants exceeding EWG health guidelines out of 32 detected — significantly above the national average. Multiple known carcinogens were found at levels of concern.
See full Westwego water report →Donaldsonville, Louisiana
Donaldsonville has 14 contaminants exceeding EWG health guidelines out of 30 detected — significantly above the national average. Multiple known carcinogens were found at levels of concern.
See full Donaldsonville water report →Houma, Louisiana
Houma has 14 contaminants exceeding EWG health guidelines out of 29 detected — significantly above the national average. Multiple known carcinogens were found at levels of concern.
See full Houma water report →Luling, Louisiana
Luling has 14 contaminants exceeding EWG health guidelines out of 29 detected — significantly above the national average. Multiple known carcinogens were found at levels of concern.
See full Luling water report →Morgan City, Louisiana
Morgan City has 14 contaminants exceeding EWG health guidelines out of 29 detected — significantly above the national average. Multiple known carcinogens were found at levels of concern.
See full Morgan City water report →Lockport, Louisiana
Lockport has 14 contaminants exceeding EWG health guidelines out of 26 detected — significantly above the national average. Multiple known carcinogens were found at levels of concern.
See full Lockport water report →Monroe, Louisiana
Monroe has 14 contaminants exceeding EWG health guidelines out of 26 detected — significantly above the national average. Multiple known carcinogens were found at levels of concern.
See full Monroe water report →Barksdale AFB, Louisiana
Barksdale AFB has 14 contaminants exceeding EWG health guidelines out of 24 detected — significantly above the national average. Multiple known carcinogens were found at levels of concern.
See full Barksdale AFB water report →Milton, Louisiana
Milton has 14 contaminants exceeding EWG health guidelines out of 23 detected — significantly above the national average. Multiple known carcinogens were found at levels of concern.
See full Milton water report →Scott, Louisiana
Scott has 14 contaminants exceeding EWG health guidelines out of 23 detected — significantly above the national average. Multiple known carcinogens were found at levels of concern.
See full Scott water report →Lafayette, Louisiana
Lafayette has 14 contaminants exceeding EWG health guidelines out of 22 detected — significantly above the national average. Multiple known carcinogens were found at levels of concern.
See full Lafayette water report →Youngsville, Louisiana
Youngsville has 14 contaminants exceeding EWG health guidelines out of 22 detected — significantly above the national average. Multiple known carcinogens were found at levels of concern.
See full Youngsville water report →Ridgecrest, Louisiana
Ridgecrest has 14 contaminants exceeding EWG health guidelines out of 20 detected — significantly above the national average. Multiple known carcinogens were found at levels of concern.
See full Ridgecrest water report →Start, Louisiana
Start has 14 contaminants exceeding EWG health guidelines out of 17 detected — significantly above the national average. Multiple known carcinogens were found at levels of concern.
See full Start water report →Jefferson, Louisiana
Jefferson has 13 contaminants exceeding EWG health guidelines out of 33 detected — significantly above the national average. Multiple known carcinogens were found at levels of concern.
See full Jefferson water report →Thibodaux, Louisiana
Thibodaux has 13 contaminants exceeding EWG health guidelines out of 33 detected — significantly above the national average. Multiple known carcinogens were found at levels of concern.
See full Thibodaux water report →Gretna, Louisiana
Gretna has 13 contaminants exceeding EWG health guidelines out of 31 detected — significantly above the national average. Multiple known carcinogens were found at levels of concern.
See full Gretna water report →Convent, Louisiana
Convent has 13 contaminants exceeding EWG health guidelines out of 30 detected — significantly above the national average. Multiple known carcinogens were found at levels of concern.
See full Convent water report →Alexandria, Louisiana
Alexandria has 13 contaminants exceeding EWG health guidelines out of 29 detected — significantly above the national average. Multiple known carcinogens were found at levels of concern.
See full Alexandria water report →Benton, Louisiana
Benton has 13 contaminants exceeding EWG health guidelines out of 29 detected — significantly above the national average. Multiple known carcinogens were found at levels of concern.
See full Benton water report →What We Found: Key Patterns
The most frequently detected contaminants exceeding health guidelines across these cities are Bromodichloromethane, Chloroform, Dibromoacetic acid. These appear repeatedly across different water systems and regions.
Water quality varies significantly even within the same state, driven by local geology, agricultural activity, and industrial proximity.
Across all ranked cities, 348 contaminant readings exceed EWG health guidelines, but only 2 exceed EPA legal limits. This gap of 346 highlights how legal standards may not fully protect public health — EPA limits haven't been updated for many contaminants in decades.
Full Rankings Table
| Rank | City | State | Detected | Above Guidelines | Above Legal | People Served |
|---|---|---|---|---|---|---|
| 1 | New Orleans | LA | 34 | 15 | 0 | 291,044 |
| 2 | Napoleonville | LA | 31 | 15 | 0 | 21,366 |
| 3 | Abbeville | LA | 23 | 15 | 0 | 14,445 |
| 4 | Rayville | LA | 20 | 15 | 0 | 4,842 |
| 5 | Belle Chasse | LA | 33 | 14 | 0 | 19,644 |
| 6 | Westwego | LA | 32 | 14 | 0 | 8,534 |
| 7 | Donaldsonville | LA | 30 | 14 | 0 | 9,732 |
| 8 | Houma | LA | 29 | 14 | 0 | 105,852 |
| 9 | Luling | LA | 29 | 14 | 0 | 52,879 |
| 10 | Morgan City | LA | 29 | 14 | 0 | 12,703 |
| 11 | Lockport | LA | 26 | 14 | 0 | 81,609 |
| 12 | Monroe | LA | 26 | 14 | 0 | 57,000 |
| 13 | Barksdale AFB | LA | 24 | 14 | 0 | 13,000 |
| 14 | Milton | LA | 23 | 14 | 0 | 11,430 |
| 15 | Scott | LA | 23 | 14 | 0 | 9,216 |
| 16 | Lafayette | LA | 22 | 14 | 0 | 156,516 |
| 17 | Youngsville | LA | 22 | 14 | 0 | 17,319 |
| 18 | Ridgecrest | LA | 20 | 14 | 2 | 855 |
| 19 | Start | LA | 17 | 14 | 0 | 2,514 |
| 20 | Jefferson | LA | 33 | 13 | 0 | 275,163 |
| 21 | Thibodaux | LA | 33 | 13 | 0 | 15,810 |
| 22 | Gretna | LA | 31 | 13 | 0 | 17,802 |
| 23 | Convent | LA | 30 | 13 | 0 | 9,392 |
| 24 | Alexandria | LA | 29 | 13 | 0 | 66,798 |
| 25 | Benton | LA | 29 | 13 | 0 | 10,890 |
Frequently Asked Questions
What city has the worst tap water in Louisiana?
Based on 2026 data, New Orleans, LA has the most contaminants exceeding EWG health guidelines among the cities we analyzed.
How are cities ranked in this report?
Cities are ranked by the number of contaminants exceeding EWG health guidelines. These guidelines are typically stricter than EPA legal limits and reflect current scientific research on safe exposure levels.
Is my tap water safe if my city isn't on this list?
Not necessarily. Even cities not on this list may have contaminants of concern. We recommend checking your specific water quality using our free water scan tool.
What's the best water filter for contaminated water?
A reverse osmosis (RO) system is the most effective for removing the widest range of contaminants. For whole-home protection, a combination of RO for drinking water and a whole-home filter for showers and baths is recommended.
Related Reports
Data sources: Environmental Working Group (EWG) Tap Water Database, U.S. EPA Safe Drinking Water Information System (SDWIS)
Last updated: April 2026
Methodology: Contaminant levels are compared against both EPA legal limits (Maximum Contaminant Levels) and EWG health guidelines, which are often stricter and based on the latest scientific research.
