Permit Overview
Municipal Separate Storm Sewer Systems (MS4s) for cities with populations of 100,000 or more are regulated as Phase I MS4s under the National Pollutant Discharge Elimination System (NPDES), as required by the Clean Water Act of 1972.
Original Permit
The City was originally issued MS4 NPDES Permit No. TXS001901 in 1996 by the United States (U.S.) Environmental Protection Agency (EPA).
The NPDES Permit set forth requirements for stormwater discharges from the City's MS4, which is owned by the City and operated by the Public Works Department. Stormwater from the City's MS4 discharges to surface waters of the state which are also waters of the U.S.
Permit Renewal & Term
The original NPDES permit was renewed in 2003 under Texas Pollutant Discharge Elimination System (TPDES) Permit No. WQ0004284000 (NPDES Permit No. TXS001901). This permit is administered by the Texas Commission on Environmental Quality (TCEQ). TPDES MS4 permits have a term of 5 years.
2021 TPDES MS4 Permit(PDF, 1MB)
Municipal Separate Storm Sewer System (MS4)
Coverage Areas
The MS4 for San Antonio and Bexar County discharges water runoff to various drainage ditches, tributaries and other channels that eventually flow into the following Upper San Antonio River Basin waterways:
- Lower Cibolo Creek
- Lower Leon Creek
- Medina River (Below Medina Diversion Lake)
- Medio Creek
- Mid Cibolo Creek
- Salado Creek
- Upper Cibolo Creek
- Upper Leon Creek
- Upper San Antonio River
Resources
Permittees & Responsibilities
San Antonio's Phase I MS4 Permit is held and administered by the following permittees:
Both permittees are responsible for conducting the following:
- ensuring compliance with permit conditions related to discharges from the MS4
- implementation of an approved Storm Water Management Program (SWMP)
- annual reporting
San Antonio Storm Water Management Program (SWMP)
Permit Obligations
- Preventing and prohibiting the discharge of pollutants into the MS4 to the Maximum Extent Practicable.
- Implementation of an approved SWMP designed by the permittees which determines what measures must be in place in order to be in compliance.
Storm Water Program Components
The SWMP consists of:
- Comprehensive outline includes:
- pollution prevention measures
- treatment or removal techniques
- storm water monitoring
- use of legal authority
- other appropriate means to control the quality of storm water discharged from the MS4.
- Identification includes:
- areas of jurisdiction for both permittees
- program element applicability on a specific area basis
Required Operations & Measures
Under the Phase I MS4 permit, the City is required to oversee, manage and implement governing operations/measures for the following:
- structural controls and storm water collection system operations
- areas of new development and/or significant redevelopment
- roadways
- flood control projects
- pesticide, herbicide and fertilizer applications
- illicit discharges and improper disposal
- spill prevention and response
- industrial and high risk runoff
- construction site runoff
- public education/public participation
- monitoring program
Storm Water Fee
The City Ordinance establishes monthly storm water fees and rate schedules for San Antonio residents, businesses and other water users. The fees support:
- operations
- maintenance
- engineering and design
- capital improvements related to the City's storm water infrastructure
The storm water utility fee is billed by San Antonio Water System (SAWS). All storm water operations, drainage maintenance and enhancement projects are managed and coordinated through the Public Works department.