Water: Water Quality Standards Academy
Basic Course: Supplemental Topics (NPDES Permit 4)
- Listing Impaired Waters and Developing TMDLs
- Monitoring & Assessment
- NPDES Permit Program
- Point Source Control
- Permitting Authority
- Types of Permits
- Categories of Permits
- Permit Components
- Key Considerations
- Technology-Based Determination
- Water Quality-Based Determination
- WQBELs Process
- Step 1: Identify WQSs
- Step 2: Assess Concentration
- Pollutants of Concern
- Critical Conditions
- Dilution/Mixing Allowance
- Step 3: Establish Need
- Step 4: Calculate Limits
- Human Health Ambient Water Quality Criteria
- Aquatic Life Criteria
Types of NPDES Permits: Individual versus General Permits
An NPDES permit can be written to address discharges either from an individual point source or from a number of similar dischargers.
NPDES Individual Permit
The permitting authority writes an individual permit to address point source-specific conditions such as effluent limitations, management practices, and monitoring and reporting. The more complex the point source discharge, the more likely an individual permit is required.
For example, ACME Inc. has process wastewater that it wants to discharge to Pristine Creek. ACME submits a permit application to the State permitting authority that describes its operation and wastewater discharge. After reviewing ACME’s application and assessing the unique characteristics of the facility’s effluent, the State crafts and issues a permit that establishes facility-specific limits on pollutants of concern that ACME can discharged to Pristine Creek.
NPDES General Permit
The permitting authority writes a general permit after determining that a set of conditions regarding discharges (e.g., limits and monitoring requirements) would be applicable to a number of similar point sources in the same geographic area (e.g., facilities within a watershed that are operating similar processes). The NPDES regulations specify that the permitting authority must define the applicable geographical area and types of point sources in a general permit. (122.28)
After a general permit is issued, dischargers that think they meet the permit’s criteria can request coverage under the permit by submitting a Notice of Intent (as required by the permit) to the permitting authority.