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.

Key Changes

As Texas continues its rapid growth, the state's renewed MS4 general permit now affects existing and newly designated MS4s. The expansion of the "urban area" criteria now includes a broader range of regulated small MS4s.  This shift aligns with the latest U.S. Census data, redefining previously rural areas as urban and bringing many municipalities under the state’s stormwater management standards for the first time.

For communities new to these requirements, the update means developing a comprehensive SWMP to maintain and protect water quality.. As more municipalities adapt to the evolving permit criteria, the goal is clear: to manage stormwater more effectively, safeguarding water quality amid Texas’ ongoing development.

With these new standards, municipalities across Texas — those with existing permits, and others new to the process — face the challenge of understanding and implementing the expanded requirements. Compliance will be critical, helping communities avoid penalties while working toward sustainable water management and resilient infrastructure for the state’s future.

Compliance Requirements and Permit Deadlines

Starting Aug. 15, 2024, municipalities operating under the renewed MS4 general permit have faced new requirements that demand proactive attention to achieve or maintain compliance.

After developing or updating a SWMP, the next step is to submit a new or renewal application according to the updated permit guidelines. MS4 permit holders must also file an annual report detailing the progress of their SWMP and document achievements toward permit goals. The renewed permit emphasizes the importance of accurate and timely recordkeeping. Municipalities must maintain detailed records of all activities related to their SWMP, including public education efforts, inspection and maintenance of stormwater control measures, and any enforcement actions taken against illicit discharge.

By staying aware of these updates and requirements, municipalities can navigate the latest MS4 requirements, supporting safer and more compliant water management systems for their communities.

Navigating the updated MS4 general permit can be challenging for municipalities, but partnering with an architecture, engineering and construction (AEC) firm can significantly ease the process. AEC firms provide crucial support by guiding municipalities through permit applications and developing effective SWMPs. Their knowledge and resources help municipalities manage regulatory changes efficiently.

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