Complaint Date | | Docket Number | | Case Name | | Statute | | Region |
| | CWA-03-2021-0104FF | | John F. Kennedy Center for the Performing Arts | | | | Region 03 |
| | CWA-03-2021-0110DS | | Clarksburg Water Board | | SDWA | | Region 03 |
| | CWA-03-2022-0018DN | | Red Hill Utility, LLC | | CWA | | Region 03 |
| | CWA-03-2022-0019DN | | Amsted Graphite Materials, LLC | | | | Region 03 |
| | CWA-03-2022-0021DN | | Hanover Foods Corporation | | CWA | | Region 03 |
| | CWA-03-2022-0022DW | | Gary Lane and Chameleon LLC | | | | Region 03 |
| | CWA-03-2022-0026DN | | City of Carbondale | | CWA | | Region 03 |
| | CWA-03-2022-0031DN | | Superior Concrete Materials, Inc. | | CWA | | Region 03 |
| | CWA-03-2022-0039DW | | Paul Goodwin | | CWA | | Region 03 |
| | CWA-03-2022-0040DN | | Hiway MHC, LLC | | CWA | | Region 03 |
| | CWA-03-2022-0042DN | | Town of Selbyville | | CWA | | Region 03 |
| | CWA-03-2022-0055DN | | ZQRIC, LLC | | CWA | | Region 03 |
| | CWA-03-2022-0117DN | | Board of County Commissioners, Washington County, Maryland | | CWA | | Region 03 |
| | CWA-03-2023-0006DN | | The Washington Marina Company | | CWA | | Region 03 |
| | CWA-03-2023-0011DN | | Chemalloy Company LLC | | CWA | | Region 03 |
| | CWA-03-2023-0025DN | | The Chemours Company FC, LLC, Washington Works | | CWA | | Region 03 |
| | CWA-03-2023-0051DW | | Panhandle Homes of Berkeley County, Inc. | | CWA | | Region 03 |
| | CWA-03-2023-0058DN | | Borough of Tamaqua and Tamaqua Borough Authority | | CWA | | Region 03 |
| | CWA-03-2023-0077DN | | City of Williamsport, PA | | CWA | | Region 03 |
| | CWA-03-2023-0078CW | | CSX Transportation, Inc., Sandstone, WV Train Derailment Site | | CWA | | Region 03 |
| | CWA-03-2023-0113DN | | Mid-Centre County Authority | | CWA | | Region 03 |
| | CWA-03-2024-0003 | | State of Delaware, Delaware Department of Transportation | | CWA | | Region 03 |
| | CWA-03-2024-0006DN | | Boone’s Estates MHC, LLC and Horizon Land Management, LLC | | CWA | | Region 03 |
| | CWA-03-2024-0007DN | | Lyons Creek MHC, LLC and Horizon Land Management, LLC | | CWA | | Region 03 |
| | CWA-03-2024-0008DN | | Maryland Manor MHC, LLC and Horizon Land Management, LLC | | CWA | | Region 03 |
| | CWA-03-2024-0009DN | | Patuxent MHC, LLC and Horizon Land Management, LLC | | CWA | | Region 03 |
| | CWA-03-2024-0016DN | | Delaware Department of Transportation | | CWA | | Region 03 |
| | CWA-03-2024-0019DN | | City of Charles Town and Charles Town Utility Board | | CWA | | Region 03 |
| | CWA-03-2024-0021DN | | Lawrenceville Borough | | CWA | | Region 03 |
| | CWA-03-2024-0035DN | | Frederick-Winchester Service Authority and Frederick County Sanitation... | | CWA | | Region 03 |
| | CWA-03-2024-0037DN | | Felman Production, LLC | | CWA | | Region 03 |
| | CWA-03-2024-0039DN | | AdvanSix Resins & Chemicals LLC, Hopewell Plant | | CWA | | Region 03 |
| | CWA-03-2024-0053DN | | Virginia Truck Parts, Inc. | | CWA | | Region 03 |
| | CWA-03-2024-0066DW | | Howard H. Holzmacher, Sr., Howard H. Holzmacher, Jr., and North Landin... | | CWA | | Region 03 |
| | CWA-03-2024-0076DN | | City of Petersburg, VA | | CWA | | Region 03 |
| | EPCRA-03-2024-0098 | | Erie Hard Chrome, Inc. | | EPCRA | | Region 03 |
| | FIFRA-03-2018-0117SS | | Alex C. Ferguson, LLC | | FIFRA | | Region 03 |
| | FIFRA-03-2024-0068SS | | Dollars Trends Inc. | | | | Region 03 |
| | FIFRA-03-2024-0079 | | Pallet Machinery Group, Inc. | | FIFRA | | Region 03 |
| | III-2001-0007-DC | | City of Philadelphia, Enterprise Avenue Landfill/Philadelphia Internat... | | | | Region 03 |
| | III-94-26-DC | | Occidental Chemical Corp. Superfund Site | | | | Region 03 |
| | RCRA-03-2013-0105CA | | ALCATEL-LUCENT USA INC., Richmond Works Facility | | | | Region 03 |
| | RCRA-03-2018-0042 | | The Former Hercules Facility | | | | Region 03 |
| | RCRA-03-2018-0143CA | | ArcelorMittal Weirton LLC, Weirton Steel facility | | | | Region 03 |
| | RCRA-03-2018-0144CA | | Mingo Junction Steel Works, LLC, Weirton Steel facilty | | | | Region 03 |
| | RCRA-03-2020-0016TH | | Budd Site, PA Opportunity Park QOF 3 | | | | Region 03 |
| | RCRA-03-2020-0035TH | | Budd Site, PA Opportunity Park QOF 1 | | | | Region 03 |
| | RCRA-03-2020-0036TH | | Budd Site, PA Opportunity Park QOF 4 | | | | Region 03 |
| | RCRA-03-2020-0037TH | | Budd Site, PA Opportunity Park QOF 5 | | | | Region 03 |
| | RCRA-03-2021-0022TH | | National Aeronautics and Space Administration - Wallops FUDS Program, ... | | | | Region 03 |
| | RCRA-03-2022-0061CA | | Pennzoil-Quaker State Company dba SOPUS Products | | RCRA | | Region 03 |
| | RCRA-03-2022-0138CA | | Excalibur Realty Company | | RCRA | | Region 03 |
| | RCRA-03-2023-0024 | | Wheeler & Wheeler, Inc. d/b/a West End Motors | | RCRA | | Region 03 |
| | RCRA-03-2023-0046CA | | Transport Pool Corporation (former General Electric Railcar Repair Ser... | | RCRA | | Region 03 |
| | RCRA-03-2023-0112CA | | Mountain State Carbon, LLC, Mountain State Carbon Coke Plant | | RCRA | | Region 03 |
| | RCRA-03-2024-0038 | | Halifax County School Board | | RCRA | | Region 03 |
| | RCRA-HQ-2024-001 | | The Chemours Company FC, LLC, Washington Works | | RCRA | | Region 03 |
| | SDWA-03-2018-0068DU | | ARG Resources, Inc. | | | | Region 03 |
| | SDWA-03-2019-0025DS | | United States Department of the Navy, Joint Base Anacostia-Bolling | | | | Region 03 |
| | SDWA-03-2020-0009DU | | Resources Preservation, Inc. f/k/a ARG Resources, Inc. | | | | Region 03 |
| | SDWA-03-2022-0038DU | | Resources Preservation, Inc., f/k/a ARG Resources, Inc. | | | | Region 03 |
| | SDWA-03-2022-0081DS | | National Railroad Passenger Corporation d/b/a Amtrak | | SDWA | | Region 03 |
| | SDWA-03-2022-0094DS | | Potomac Farms LLC | | SDWA | | Region 03 |
| | SDWA-03-2022-0142DS | | Logan County Public Service District, Northern Regional | | SDWA | | Region 03 |
| | SDWA-03-2022-0143DS | | Logan County Public Service District, Greenville | | SDWA | | Region 03 |
| | SDWA-03-2023-0005 | | Bear Lake Properties, LLC | | SDWA | | Region 03 |
| | SDWA-03-2023-0057DS | | Nelson County Service Authority, Wintergreen Water System | | SDWA | | Region 03 |
| | SDWA-03-2023-0061DS | | Dickenson County Public Service Authority, Big Caney | | SDWA | | Region 03 |
| | SDWA-03-2023-0062DS | | Cheat View Public Service District | | SDWA | | Region 03 |
| | SDWA-03-2024-0030DS | | Leadsville Public Services District | | SDWA | | Region 03 |
| | TSCA-03-2021-0055 | | Prominent Painters, LLC d/b/a Fresh Coat Painters of Charleston | | TSCA | | Region 03 |
| | TSCA-03-2021-0057 | | Omar B. Construction LLC | | TSCA | | Region 03 |
| | TSCA-03-2023-0045 | | I360 Rentals | | TSCA | | Region 03 |