What the Renewed MS4 Permit Means for Texas Municipalities

The Texas Commission on Environmental Quality (TCEQ) is leading the charge for regulatory updates to protect Texas waterways. As part of the Clean Water Act’s framework, National Pollutant Discharge Elimination System (NPDES) permits, including Texas’ Phase II Municipal Separate Storm Sewer System (MS4) general permit, are limited to a maximum term of five years. The recent renewal of TCEQ’s 2019 Phase II MS4 general permit marks a significant step in strengthening water quality protections as the state navigates unprecedented urban growth. The renewal period remains open until February 2025, offering permittees time to comply; enforcement actions could begin after that deadline.

What Is a MS4?

A MS4 refers to a network or system of structures — including roads with drainage systems, municipal streets, catch basins, curbs, gutters, ditches, human-made channels and storm drains — owned or operated by a public entity. The main objective of a MS4 is to minimize the discharge of pollutants in stormwater runoff, thus protecting water quality and complying with the Clean Water Act.

Permit holders are required to develop and implement a stormwater management program (SWMP) that incorporates several minimum control measures (MCMs). These MCMs form the core of a comprehensive stormwater management approach:

Public education and outreach. Educating the public about the effects of stormwater discharges on water bodies and providing guidance on how to reduce pollutants.
Public involvement. Encouraging community engagement and participation in local efforts to reduce stormwater pollution.
Illicit discharge detection and elimination. Identifying and removing unauthorized discharges into the storm sewer system.
Construction site stormwater runoff control. Managing stormwater runoff from construction sites to reduce pollutants entering the storm sewer system.
Post-construction stormwater management in new development and redevelopment. Implementing long-term strategies to manage stormwater for new and redeveloped areas.
Pollution prevention and good housekeeping for municipal operations. Minimizing stormwater pollution involving municipal operations.
Industrial stormwater sources. Managing stormwater discharges from industrial sites, which can be major sources of pollutants; required only if the MS4 serves a population of more than 100,000.
Authorization of construction activities when the small MS4 serves as the site operator (optional). Maintaining MS4 authorization, including oversight of the plans and specifications for each construction activity, if serving as site operator.