waterbycounty

Louisiana Water Quality

Drinking water data for all 64 counties.

Avg Water Score

30.1

State Grade

F

Counties with Data

63

of 64 total

All Louisiana Counties

CountyWater Score
Assumption Parish86.0
Lafourche Parish86.0
St. Bernard Parish86.0
St. Charles Parish86.0
St. John the Baptist Parish86.0
Terrebonne Parish86.0
East Baton Rouge Parish70.4
Jefferson Parish69.0
Orleans Parish65.8
West Baton Rouge Parish65.3
West Feliciana Parish62.8
Jefferson Davis Parish58.3
East Feliciana Parish51.3
Rapides Parish46.5
Beauregard Parish44.8
Calcasieu Parish43.6
Lafayette Parish41.1
Livingston Parish40.6
Pointe Coupee Parish40.0
St. Tammany Parish36.4
Vernon Parish36.3
Tangipahoa Parish35.4
Iberia Parish33.5
Vermilion Parish27.1
Avoyelles Parish27.0
Catahoula Parish25.7
Washington Parish25.5
Caddo Parish23.8
St. Helena Parish23.8
St. Landry Parish23.7
St. James Parish23.4
Webster Parish23.1
Ascension Parish21.8
Bossier Parish21.6
Ouachita Parish20.8
St. Martin Parish19.8
Allen Parish18.9
Franklin Parish18.8
Claiborne Parish18.7
Evangeline Parish16.9
West Carroll Parish16.8
Acadia Parish16.0
St. Mary Parish14.4
Iberville Parish14.1
Madison Parish14.0
Lincoln Parish12.5
Plaquemines Parish10.5
Richland Parish9.8
Morehouse Parish6.6
Natchitoches Parish5.6
De Soto Parish5.2
Grant Parish5.0
East Carroll Parish4.9
Red River Parish3.1
Jackson Parish3.0
Caldwell Parish2.9
Concordia Parish2.8
Bienville Parish2.3
Cameron Parish2.3
Sabine Parish1.8
Tensas Parish1.7
Union Parish1.2
Winn Parish0.9
LaSalle Parish—

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Frequently Asked Questions

Which county in Louisiana has the best water quality?
Assumption Parish has the highest water quality score in Louisiana at 86.0/100 (Grade: A), based on EPA SDWIS data.
Which county in Louisiana has the most water violations?
Winn Parish has among the lowest water quality scores in Louisiana at 0.9/100. See the individual county page for detailed violation history.
Is the tap water safe to drink in Louisiana?
Louisiana has an average water quality score of 30.1/100 based on EPA Safe Drinking Water Act compliance data. Individual county scores vary — check your specific county's page for detailed information.
What contaminants are found in Louisiana water supplies?
Drinking water quality varies by county and water system. The EPA Safe Drinking Water Information System (SDWIS) tracks violations for contaminants like lead, nitrates, bacteria, and disinfection byproducts. See individual county pages for specific contaminant and violation history.

Data Source

Water quality data sourced from the EPA Safe Drinking Water Information System (SDWIS) via the ECHO enforcement database. Scores reflect compliance history and health-based violation counts.

Disclaimer: This data is informational only. It is not health, legal, or professional advice. For concerns about your specific water supply, contact your local water utility.

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