What is the largest Clean Water Act penalty ever assessed?

BP EXPLORATION/MOEX/TRANSOCEAN DEEPWATER/TRITON/GULF OF MEXICO OIL SPILL/DEEPWATER HORIZON (NC): $3,367.3 million in fiscal year 2010, with $1,943.8 million in required compliance actions. Penalties are the amounts EPA records as assessed or agreed, which can differ from what was collected.

Which state has the most EPA enforcement actions against wastewater plants?

Texas, with 510 formal cases naming 275 plants, 148 of the cases since fiscal year 2020. Counts reflect federal cases in EPA's ICIS system; state-led enforcement is recorded separately by each state.

What is the difference between an administrative and a judicial enforcement case?

Administrative cases are handled by EPA itself, usually as orders under section 309 of the Clean Water Act that require a plant to correct permit violations, sometimes with a penalty. Judicial cases are referred to the Department of Justice and filed in court; they typically end in a consent decree that sets a multi-year capital programme, which is why the largest compliance-action values sit with judicial cases.

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EPA enforcement against wastewater plants and the largest Clean Water Act penalties

Name: EPA enforcement actions against US wastewater treatment plants
Creator: Klarifi
License: https://klarifi.io/terms-of-service

2,747 formal cases at 1,522 plants · $266M in penalties · 884 EPA inspections

2,747

formal cases at 1,522 wastewater plants

548

of them since FY2020

$266M

penalties assessed at plants

9,132

Clean Water Act cases nationwide, $7,450M in penalties

EPA's civil enforcement records name 1,522 of the 11,774 publicly owned wastewater treatment plants in the Klarifi directory in 2,747 formal cases, with $266.3 million in penalties assessed. Across all facility types, EPA has brought 9,132 cases under the Clean Water Act with $7,449.5 million in penalties. The state table links to each state's enforcement page, and the ranking below lists the largest Clean Water Act penalties on record, wastewater plants and industrial dischargers alike. Every case links to its report on EPA's ECHO site.

Facility directory →NPDES permit lookup →The 50 largest US plants →Analysis: enforcement since 2020 →

Enforcement against wastewater plants by state

State	Formal cases	Since FY2020	Plants named	Penalties
Texas	510	148	275	$175M
New York	300	45	136	$5.8M
Louisiana	178	23	76	$1.2M
New Mexico	156	60	23	$717,007
Ohio	117	31	83	$10M
Missouri	108	16	74	$7M
Idaho	102	15	54	$1.2M
Pennsylvania	99	17	60	$2.6M
New Jersey	93	7	39	$2M
Massachusetts	89	11	37	$1.2M
Indiana	60	4	32	$5.7M
Illinois	52	17	37	$11M
New Hampshire	52	7	19	$412,750
Alabama	48	0	27	$4.9M
Michigan	45	3	31	$1M
South Carolina	42	3	24	$701,222
Oklahoma	41	9	30	$496,890
Tennessee	41	9	28	$3.5M
California	38	6	26	$2.4M
Kansas	38	10	29	$177,188
Arkansas	37	5	22	$783,649
Nebraska	37	10	29	$1.1M
West Virginia	37	15	32	$4.5M
Florida	35	0	24	$2.6M
Iowa	35	5	27	$88,920
Arizona	32	6	19	$1M
Wisconsin	32	16	18	$297,674
Washington	26	10	20	$655,249
Georgia	24	2	16	$3.1M
Mississippi	24	11	20	$722,158
Montana	24	3	14	$709,325
Connecticut	22	0	14	$2M
Kentucky	22	0	16	$2.6M
Colorado	20	5	17	$1.2M
Virginia	18	0	15	$226,130
Minnesota	17	7	13	$4.4M
Alaska	16	3	9	$353,818
Maryland	16	2	8	$1.7M
Rhode Island	13	0	9	$283,000
North Carolina	11	0	7	$8,300
Oregon	11	2	9	$62,110
South Dakota	8	1	5	$5,375
Maine	6	1	5	$27,500
Utah	5	0	5	$10,025
Wyoming	4	2	3	$12,500
Hawaii	3	0	3	—
Delaware	1	1	1	—
North Dakota	1	0	1	$7,650
Vermont	1	0	1	$10,521

Full case histories, milestones, violation types and EPA's complete case summaries for every plant are shown with a free Klarifi account. Create one →

The 10 largest Clean Water Act penalties

EPA civil cases with a Clean Water Act count, ranked by the penalty assessed or agreed. Cases may include counts under other statutes; the Deepwater Horizon settlement leads the list. Compliance actions are the value of the fixes and upgrades a case required.

The 10 largest penalties in EPA civil enforcement cases brought under the Clean Water Act, all facility types, ranked by penalty assessed. Source: EPA ICIS-FE&C civil enforcement cases and ICIS compliance inspections, via ECHO.
#	Case	State	Date	Type	Penalty	Compliance actions	Source
1	BP EXPLORATION/MOEX/TRANSOCEAN DEEPWATER/TRITON/GULF OF MEXICO OIL SPILL/DEEPWATER HORIZON (NC)	TX	Apr 2016 · FY2010	Judicial case	$3,367M	$1,944M	ECHO 04-2010-9036
EPA's description: “5/9/2011 - COMPLAINT ALLEGES DEFENDANTS VIOLATED CWA SECTIONS 311 AND 301/402. THE VIOLATIONS AROSE FROM OIL DISCHARGES FROM THE MOBILE OFFSHORE DRILLING UNIT, DEEPWATER HORIZON, IN THE GULF OF…”
2	ATP Oil & Gas Corp.	TX	Dec 2015 · FY2013	Judicial case	$39M	$5,000	ECHO 06-2013-1792
EPA's description: “Complaint alleging the unlawful discharges of oil and an unpermitted chemical dispersant from the offshore oil and gas production platform, known as the ATP Innovator, into the Gulf of Mexico. A…”
3	BP EXPLORATION (ALASKA) INC (BPXA)	AK	Nov 2015 · FY2006	Judicial case	$25M	$61M	ECHO 10-2006-0316
EPA's description: “U.S. District Court for the District of Alaska Enters Consent Decree for BP Exploration Alaska (BPXA) Violations of Clean Water Act, Clean Air Act, and Federal Pipeline Safety Laws. On July 13, 2011,…”
4	DISTRICT OF COLUMBIA (BLUE PLAINS	DC	Aug 1996 · FY1996	Judicial case	$20M	$110M	ECHO 03-1996-0072
5	KOCH INDUSTRIES, INC.	KS	Jul 2009 · FY1995	Judicial case	$15M	—	ECHO 06-1995-0015
6	MASSEY ENERGY COMPANY, ET. AL.(NATIONAL CASE)(LEAD)	WV	Apr 2008 · FY2005	Judicial case	$13M	$7.1M	ECHO 03-2005-0380
7	SMITHFIELD FOODS, INC.	VA	Feb 2001 · FY1996	Judicial case	$13M	—	ECHO 03-1996-0278
8	MOTIVA ENTERPRISES, LLC , ET AL	DE	Jan 2006 · FY2001	Judicial case	$12M	$10M	ECHO 03-2001-0334
9	MORTON INTERNATIONAL, INC. (NATIONAL CASE) (LEAD)	MS	Nov 2005 · FY1998	Judicial case	$10M	$42M	ECHO 04-1998-0459
10	DOE RUN RESOURCES CORPORATION	MO	Dec 2011 · FY2007	Judicial case	$7M	$66M	ECHO 07-2007-0275

Cases by fiscal year

Fiscal year	At wastewater plants	Penalties at plants	All Clean Water Act cases	Penalties, all CWA
FY2017	56	$4.4M	182	$11M
FY2018	71	$497,080	208	$4.6M
FY2019	68	$130,468	228	$8.8M
FY2020	59	$35,100	210	$7.6M
FY2021	53	$129,500	232	$4.6M
FY2022	76	$859,494	245	$7M
FY2023	88	$335,321	277	$3.6M
FY2024	110	$87,975	330	$5.1M
FY2025	82	$218,603	250	$2.1M
FY2026	80	$26,700	180	$1.2M

EPA fiscal years run from 1 October to 30 September. The current year is partial.

EPA wastewater enforcement: 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 September 17, 2026.

Enforcement data: EPA ICIS-FE&C civil enforcement cases and ICIS compliance inspections, via ECHO. Penalties are the amounts assessed or agreed in each case as EPA records them, not necessarily collected.

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