waterbycounty

Oklahoma Water Quality

Drinking water data for all 77 counties.

Avg Water Score

15.8

State Grade

F

Counties with Data

77

of 77 total

All Oklahoma Counties

CountyWater Score
Harper County86.0
Love County86.0
Tulsa County70.4
Oklahoma County63.8
Pontotoc County46.4
Beckham County41.6
Woodward County40.4
Mayes County39.2
Texas County35.9
Woods County33.0
Harmon County32.5
Cimarron County32.4
Custer County31.6
McClain County30.3
Cleveland County29.8
Comanche County29.2
Garfield County29.2
Ottawa County29.2
Logan County28.9
Ellis County26.9
Creek County24.8
Beaver County21.9
Payne County19.9
Sequoyah County18.3
Adair County17.4
Rogers County15.9
Canadian County13.2
Kay County12.7
Grady County12.2
Stephens County11.6
Washington County11.5
Washita County11.2
Murray County11.0
Carter County10.8
Dewey County10.8
Delaware County10.4
Blaine County9.3
Craig County8.5
Alfalfa County8.4
Bryan County7.5
Johnston County7.2
Roger Mills County6.9
Cherokee County6.4
Okfuskee County6.3
Pottawatomie County5.4
Marshall County5.3
Kiowa County4.5
Wagoner County4.5
Greer County4.2
Muskogee County4.1
Jackson County4.0
Grant County3.9
Noble County3.9
Caddo County3.8
Coal County3.5
Lincoln County3.3
Le Flore County3.2
Kingfisher County3.0
Garvin County2.8
Okmulgee County2.8
Hughes County2.6
McCurtain County2.3
McIntosh County2.3
Pittsburg County2.1
Cotton County1.5
Tillman County1.4
Major County1.3
Seminole County1.3
Latimer County1.1
Jefferson County1.0
Pawnee County0.9
Nowata County0.7
Atoka County0.6
Osage County0.6
Haskell County0.5
Pushmataha County0.4
Choctaw County0.3

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Frequently Asked Questions

Which county in Oklahoma has the best water quality?
Harper County has the highest water quality score in Oklahoma at 86.0/100 (Grade: A), based on EPA SDWIS data.
Which county in Oklahoma has the most water violations?
Choctaw County has among the lowest water quality scores in Oklahoma at 0.3/100. See the individual county page for detailed violation history.
Is the tap water safe to drink in Oklahoma?
Oklahoma has an average water quality score of 15.8/100 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 Oklahoma 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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