What is the largest wastewater treatment plant in Oklahoma?

Okc South Canadian Wwt in Oklahoma City, treating an average of 37.17 MGD under NPDES permit OK0036978. Northside Wastewater Treatment Plant in Tulsa is second at 23.36 MGD.

How much wastewater do Oklahoma’s largest plants treat?

The 50 largest plants treat 234 MGD combined, 87% of the flow reported by all 236 publicly owned plants in Oklahoma.

How is plant size measured?

By reported average daily flow in million gallons per day (MGD) from EPA discharge monitoring reports, the standard measure of a plant’s size. Design capacity, the flow a plant is permitted to treat, is usually higher and is shown on each profile.

Try for free Log in

The 50 largest wastewater treatment plants in Oklahoma

Name: Largest wastewater treatment plants in Oklahoma
Creator: Klarifi
License: https://klarifi.io/terms-of-service

Ranked by average flow · 234 MGD combined · 87% of the state's reported flow

Okc South Canadian Wwt in Oklahoma City is the largest publicly owned wastewater treatment plant in Oklahoma by reported average flow, treating about 37.17 million gallons per day. The 50 plants below treat 234 MGD between them, 87% of the flow reported by all 236 plants in the state, and serve about 1,765,462 people. Every plant links to its profile with permit and compliance data. Treatment technology is shown with a free Klarifi account.

All plants in Oklahoma →The 50 largest US plants →Oklahoma NPDES permits →

The 50 largest publicly owned wastewater treatment plants in Oklahoma by average flow (MGD), with population served, NPDES permit, expiry and three-year violation count.
#	Facility	City	Avg flow (MGD)	Population	NPDES permit	Expires	Violations (3y)
1	Okc South Canadian Wwt	Oklahoma City	37.17	40,017	OK0036978	Jul 2029	188
2	Northside Wastewater Treatment Plant	Tulsa	23.36	181,670	OK0026221	Feb 2028	19
3	Tmua South	Tulsa	20.88	147,101	OK0026239	May 2029	21
4	Ok City Water Util Trst-Deer Ck	Oklahoma City	12.86	124,013	OK0027561	Aug 2029	41
5	Haikey Creek Wastewater Treatment Plant	Broken Arrow	12.67	112,205	OK0034363	Apr 2030	3
6	Norman (main) Wwt	Norman	9.95	128,026	OK0029190	Oct 2030	59
7	Lawton, City Of	Lawton	8.95	91,687	OK0035246	Sep 2030	171
8	Edmond, City Of - Coffee Creek	Edmond	6.91	74,307	OK0026026	Oct 2030	20
9	Midwest City Wwt	Oklahoma City	5.66	57,288	OK0026841	Apr 2020	42
10	Lynn Lane Waste Water Treatment Plant	Broken Arrow	5.55	90,643	OK0040053	Apr 2030	51
11	Ok City Water Util Trst-Chisholm	Edmond	5.33	74,455	OK0027553	Aug 2029	23
12	City Of Muskogee Pollution Control Plant	Muskogee	5.23	36,790	OK0029131	Dec 2030	43
13	City Of Moore WWTP	Moore	5.08	49,345	OK0027391	Dec 2028	3
14	Oowa / Tsc	Pryor	4.94	—	OK0034568	Aug 2029	2
15	Stillwater, City Of	Stillwater	4.64	41,163	OK0027057	Mar 2028	12
16	Tahlequah Pwa	Tahlequah	4.17	16,463	OK0026964	Jun 2010	220
17	Ponca City, City Of	Ponca City	3.9	27,311	OK0026069	Mar 2031	0
18	Okmulgee WWTP	Okmulgee	3.16	13,721	OK0028134	May 2022	101
19	Owasso Public Works Authority	Owasso	2.98	19,496	OK0020303	Jul 2028	4
20	Shawnee Municipal Auth- North	Shawnee	2.97	7,558	OK0037893	Jan 2023	26
21	Enid, City Of	Enid	2.89	49,583	OK0021628	Jul 2029	8
22	City Of Ardmore Wastewater Treatment Plant	Ardmore	2.65	25,352	OK0038440	Apr 2029	168
23	Sapulpa WWTF	Sapulpa	2.63	23,073	OK0043974	Aug 2030	76
24	Bixby Pulbic Works Auth -South	Bixby	2.42	6,660	OK0026913	Feb 2029	50
25	Yukon, City Of	Yukon	2.38	23,339	OK0028584	Sep 2029	43
26	Altus SE Wastewater Treatment Plant	Altus	2.14	17,853	OK0028037	Apr 2030	150
27	Jenks Wastewater Treat. Plant	Jenks	1.95	10,070	OK0037401	Aug 2030	18
28	Del City Municipal Svcs. Auth	Del City	1.9	24,067	OK0026085	Jul 2027	8
29	Miami WWTF-SE Plant	Miami	1.88	13,176	OK0031798	Sep 2031	2
30	Sand Springs Main WWTP	Sand Springs	1.78	18,094	OK0030864	Feb 2031	41
31	Poteau, City Of	Poteau	1.7	8,365	OK0021610	Jan 2027	4
32	Foss Reservoir M.C.D.	Foss	1.69	—	OK0041491	May 2012	0
33	Durant City Utilities Auth	Durant	1.52	18,589	OK0039063	May 2030	210
34	Mcalester, City Of - West Plant	Mcalester	1.45	9,368	OK0026093	May 2026	96
35	City Of Sallisaw Solid Waste Disposal Facility	Sallisaw	1.42	8,410	OK0028169	Oct 2030	17
36	Chickasha WWTP	Chickasha	1.41	18,210	OK0026018	Dec 2026	6
37	Mustang Improvement Authority	Mustang	1.37	14,594	OK0026816	Nov 2028	95
38	Duncan Public Utilities Auth	Duncan	1.37	23,714	OK0026638	Jul 2028	380
39	Shawnee Municipal Auth-South	Shawnee	1.33	22,675	OK0026051	Nov 2024	22
40	El Reno Municipal Authority	El Reno	1.13	—	OK0100382	Sep 2027	34
41	Stilwell Area Development Auth	Stilwell	1.12	3,452	OK0030341	Oct 2030	39
42	Weatherford Public Works Authority	Weatherford	1.11	11,415	OK0021563	Jul 2028	1
43	Hugo Municipal Authority	Hugo	1.11	5,853	OK0028487	Nov 2028	140
44	Idabel Public Works Authority	Idabel	1.1	7,408	OK0027677	Jun 2029	118
45	Pryor Creek WWTP	Pryor	1.07	9,253	OK0040479	Oct 2028	4
46	Pauls Valley Wwt	Pauls Valley	1.06	6,617	OK0039071	Apr 2031	146
47	Coweta Pwa	Coweta	1.04	7,522	OK0020281	May 2021	108
48	Mcalester East WWTP	Mcalester	1.03	9,370	OK0026107	Dec 2026	50
49	Tulsa MUA-Lower Bird Ck Plant	Catoosa	1.03	17,371	OK0042935	Jul 2029	0
50	Guymon City Of	Guymon	0.96	18,750	OK0045713	Mar 2027	21

Treatment technology for each plant is shown with a free Klarifi account. Create one →

Largest plants in Oklahoma: questions

Sources and methodology

Flow, permit and violation figures come from the EPA's ICIS-NPDES discharge monitoring records. Population served comes from the Clean Watersheds Needs Survey 2022. Treatment structures are identified by Klarifi's review of aerial imagery, and capital improvement projects are extracted from published municipal budget documents. Violations are counted over the last three years of monitoring reports.

Data refreshed October 26, 2026.

Wastewater terms: WWTP · POTW · MGD · NPDES permit · Sludge dewatering · Biological nutrient removal · all terms

Cite this page

Journalists, researchers and educators are welcome to quote these figures. Please credit Klarifi as the source and link to this page.

Klarifi. “Largest wastewater treatment plants in Oklahoma (2026).” Updated October 26, 2026. https://klarifi.io/facilities/oklahoma/largest

Need a custom cut of the data for a state, a county or a list of plants? Email info@klarifi.io.

Try Klarifi for free

Create your own trial account and explore how Klarifi can help you.

Try for free