| #R001 | reporting | reporting | mandatory | Electronic Reporting Requirement | wastewater | It requires permittees and regulators to use existing, available information technology to electronically report information and data related to the NPDES permit program in lieu of filing paper-based reports. | Substitution of electronic reporting for paper-based reports | high |
| #R002 | monitoring | operational | mandatory | Sufficiently Sensitive Test Methods | wastewater | only "sufficiently sensitive" analytical test methods may can be used when completing an NPDES permit application and when performing sampling and analysis pursuant to monitoring requirements in an NPDES permit. | When completing an NPDES permit application or performing sampling and analysis pursuant to monitoring requirements | high |
| #R003 | treatment | operational | mandatory | Cooling Water Intake Mortality Reduction Options | aquatic life | The facilities are required to choose one of seven options to reduce mortality to fish and other aquatic organisms. | roughly 1,065 existing facilities that are designed to withdraw at least 2 million gallons per day of cooling water | high |
| #R004 | monitoring | operational | mandatory | Cooling Water Intake Site-Specific Studies | aquatic life | Facilities that withdraw at least 125 million gallons per day must conduct studies to help their permitting authority determine whether and what site-specific controls, if any, would be required to further reduce mortality of aquatic organisms. | Facilities that withdraw at least 125 million gallons per day | high |
| #R005 | design | operational | mandatory | Cooling Water Intake New Unit Mortality Reduction | aquatic life | New units added to an existing facility are required to reduce mortality of aquatic organisms that achieves one of two alternatives under national entrainment standards. | New units added to an existing facility | high |
| #R006 | reporting | health | mandatory | Great Lakes CSO Public Notification Requirements | wastewater, recreational water | The requirements address signage, initial notification of local public health departments and other potentially affected entities, initial notification of the public, annual notice provisions, and development of a public notification plan. | combined sewer discharges (CSOs) to the Great Lakes | high |