Nitrate-Nitrite (Combined) violations in Oklahoma
236 active public water systems in Oklahoma had a Nitrate-Nitrite (Combined) violation in the past three years, 8 of them in the latest quarter of EPA's data. What Nitrate-Nitrite (Combined) is and why it matters.
Systems with a Nitrate-Nitrite (Combined) violation
Latest quarter first, then largest first| System | Serves | Status | Rules violated, 3 yr | Unresolved |
|---|---|---|---|---|
|
Tillman CO Rwd #1 Tillman County |
1,500 | 5 | 1 | |
|
Grandfield Tillman County |
1,110 | 2 | 0 | |
|
Tipton Tillman County |
916 | 7 | 3 | |
|
Canadian CO Rwd # 1 Canadian County |
750 | 3 | 0 | |
|
Calumet Pwa Canadian County |
600 | 4 | 0 | |
|
Dill City Washita County |
526 | 7 | 1 | |
|
Okarche Rwd, INC Kingfisher County |
250 | 5 | 0 | |
|
Aline, Town of Alfalfa County |
214 | 5 | 0 | |
|
Midwest City Oklahoma County |
55,935 | 3 | 1 | |
|
Mustang, City of Canadian County |
18,576 | 5 | 2 | |
|
Okmulgee Pwa Okmulgee County |
13,495 | 6 | 0 | |
|
Guymon Texas County |
11,442 | 2 | 0 | |
|
Clinton Custer County |
8,883 | 8 | 1 | |
|
Jefferson CO Cons Rwd #1 Jefferson County |
8,398 | 3 | 0 | |
|
Noble Utilities Authority Cleveland County |
5,750 | 4 | 0 | |
|
Collinsville Tulsa County |
5,400 | 4 | 0 | |
|
Alva Woods County |
5,208 | 5 | 1 | |
|
Tri-County Rwd #2 Pottawatomie County |
5,172 | 3 | 0 | |
|
Nichols Hills Oklahoma County |
4,020 | 5 | 0 | |
|
Grady CO Rwd #6 Grady County |
3,930 | 11 | 0 | |
|
Elgin Pwa Comanche County |
3,300 | 9 | 1 | |
|
New Cordell Utility Authority Washita County |
2,903 | 5 | 0 | |
|
Cheyenne Arapaho Concho County |
2,862 | 1 | 0 | |
|
Roland Sequoyah County |
2,842 | 1 | 0 | |
|
Watonga Blaine County |
2,816 | 4 | 1 | |
|
Stigler Haskell County |
2,731 | 2 | 0 | |
|
Fairview Major County |
2,690 | 5 | 1 | |
|
Jackson CO Water Corp Jackson County |
2,662 | 7 | 2 | |
|
Commerce Ottawa County |
2,645 | 7 | 1 | |
|
Walters Public Works Authority Cotton County |
2,551 | 2 | 1 | |
|
Lincoln CO RW & Sewer Dist 4 Lincoln County |
2,525 | 3 | 0 | |
|
Bowlegs Lima Water Seminole County |
2,500 | 5 | 0 | |
|
Oklahoma City Zoo Oklahoma County |
2,500 | 5 | 0 | |
|
Jay Delaware County |
2,482 | 4 | 1 | |
|
Hollis Harmon County |
2,264 | 3 | 1 | |
|
Wagoner Co. Rwd #2 Wagoner County |
2,000 | 10 | 0 | |
|
Comanche Public Works Authority Stephens County |
1,649 | 5 | 0 | |
|
Logan CO Rws & Swmd #3 Logan County |
1,618 | 4 | 0 | |
|
Locust Grove Pwa Mayes County |
1,600 | 5 | 0 | |
|
Beckham CO Rwd # 1 Beckham County |
1,595 | 2 | 0 | |
|
Apache Caddo County |
1,521 | 4 | 0 | |
|
Osage CO Rwd #21 Osage County |
1,500 | 9 | 4 | |
|
Oilton Creek County |
1,435 | 14 | 5 | |
|
Afton Pwa Ottawa County |
1,428 | 5 | 1 | |
|
Geary Blaine County |
1,258 | 8 | 1 | |
|
Mooreland Woodward County |
1,226 | 4 | 0 | |
|
Panhandle State University Texas County |
1,200 | 5 | 1 | |
|
Medford Grant County |
1,172 | 3 | 0 | |
|
Okarche Kingfisher County |
1,110 | 2 | 1 | |
|
Frontier City Oklahoma County |
1,040 | 6 | 1 |
About this data
A system is counted once if any of its violations in the past three years involved Nitrate-Nitrite (Combined), including monitoring and reporting lapses. Rules violated and status in the table are for the whole system, not Nitrate-Nitrite (Combined) alone.
Source: the U.S. EPA's Enforcement and Compliance History Online system (ECHO), which publishes the federal Safe Drinking Water Information System. EPA's terms and values are shown as published. The Oklahoma records are from EPA's data refresh of Oct 7, 2026; EPA refreshes this data quarterly, and states report to EPA with a lag of three to six months, so the newest violations may not appear yet.