Small MS4 Update: How Will the TPDES Change Impact You?


DURATION 5 minute read

On January 16, 2019, the Texas Commission on Environmental Quality (TCEQ) renewed the Texas Pollutant Discharge Elimination System (TPDES) General Permit No. TXR040000, commonly known as the Small MS4 (Phase II) General Permit. The permit regulates both stormwater and certain non-stormwater discharges from publicly owned or operated small Municipal Separate Storm Sewer Systems (MS4s) into surface waters in the state. The General Permit applies to the entire State of Texas and is authorized by the Texas Water Code, §26.040.

Encouraging the public to keep Texas waterways clean by eliminating illicit discharges is one of the ways Phase II MS4s help improve stormwater quality.

If your public entity is located within an urbanized area, you may be classified as an MS4. If your municipality has not filed for permit coverage or the permit coverage has lapsed, Jones|Carter (J|C) can assist in interpreting regulatory language and implementation requirements. MS4s may include cities, municipal utility districts, flood control and drainage districts, transportation authorities, military bases, prisons, and universities.

Small MS4s located within urbanized areas (as defined by the 2010 U.S. Census) are required to apply for permit coverage. Approximately 509 Phase II MS4s in the state of Texas filed for permit coverage for the previous 2013 General Permit. The TCEQ is unsure the number of additional Phase II MS4s that will need to apply for this permit renewal. Part of the application process requires the permittee, in this case the MS4, to submit a Notice of Intent (NOI) and Storm Water Management Program (SWMP) to the TCEQ for approval.

The SWMP must be developed, implemented, and enforced according to the requirements of the General Permit. It must have components addressing the six Minimum Control Measures (MCM):

  • MCM 1. Public education, outreach, and involvement
  • MCM 2. Illicit discharge detection and elimination
  • MCM 3. Construction site stormwater runoff control
  • MCM 4. Post-construction stormwater management in new development and redevelopment
  • MCM 5. Pollution prevention and good housekeeping for municipal operations
  • MCM 6. Industrial stormwater sources (only applies if the MS4 serves a population more than 100,000)

These measures are implemented through best management practices. They must also fulfill the requirements as stated in their TCEQ-approved SWMP. The SWMP is a comprehensive five-year plan that outlines how the MS4 intends to implement permit requirements.

If your MS4 has a SWMP, it will need to be updated to remain compliant with the new permit requirements. To determine if your municipality will need to apply for permit coverage, please refer to the TCEQ’s Interactive Map of Urbanized Areas.


Waiver Eligibility

A small MS4 may be eligible to apply for a waiver if certain requirements are met. The main requirement for eligibility is population as stated below:

  • For traditional small MS4s, the residential population within the urbanized area must be less than 1,000.
  • For non-traditional small MS4s, such as universities and prisons, the number of people using the MS4 on an average operational day must be less than 1,000.

As stated previously, urbanized areas are as defined by the 2010 U.S. Census.

If the waiver is granted, the MS4 will not be required to submit an NOI or develop and implement a SWMP. However, if the waiver option is not attainable or is denied by TCEQ, the MS4 must create and enforce their SWMP.

Proposed Changes to The General Permit

This General Permit amends and renews the 2013 TPDES General Permit. Significant changes include adhering to the EPA’s National Pollutant Discharge Elimination System (NPDES) MS4 Remand Rule for Phase II communities that went into effect in January 2017. Some updates to the Phase II General Permit are summarized below:

  • The SWMP must be written in a “clear, specific, and measurable” way. Essentially, the SWMP should be worded so that compliance can be easily assessed and tracked to determine if measurable goals have been achieved.
  • Language was added regarding the annexation (or de-annexing) of land resulting in a Phase II Level change (Levels are based on population).
  • MS4s need to confirm in the annual report that waterways within their permittee area have not been added to the current Texas Integrated Report of Surface Water Quality 305(b) or 303(d)
  • The SWMP and annual reports are to be published on the MS4’s public website (if available).
  • General Permit applications and MS4 annual reports need to be submitted electronically by December 21, 2020 to be consistent with EPA’s Electronic Reporting Rule (currently TCEQ is unable to fulfill this rule).
  • Additional updates proposed for Level 4 MS4 permittees (population of 100,000 or greater).
  • MS4s or other permittees must follow the public notice requirements as stated in the General Permit, if modifications to the SWMP are necessary.

Please note that approval of a waiver for the 2013 General Permit does not guarantee waiver approval under the 2019 General Permit. Your entity will need to evaluate their eligibility and re-apply for the waiver, if applicable. 



When the General Permit becomes effective, each MS4 must submit their respective NOI and SWMP to the TCEQ within 180 days following the effective date. Failure to apply for permit coverage could result in state-issued violations with the possibility of monetary penalties.

Below is a timeline of the permit renewal process.

Stay Informed

Through our active participation in the TCEQ’s Stormwater Stakeholders Group and Water Quality Advisory Work Group, we will work to ensure our Phase II MS4 clients stay informed of ongoing permitting regulations and how their jurisdiction may be affected.

The Jones|Carter Approach

J|C can assist MS4s in fulfilling all aspects of the Phase II General Permit requirements. Our team has experience encompassing waiver requests, application submittals, the development and continuous administration of the SWMP, assisting with TCEQ compliance investigations and audits, and public outreach opportunities. The J|C team has more than 10 years of experience managing SWMPs for various MS4 clients. J|C staff consistently strive for excellence. J|C has never been cited with a violation from the TCEQ for managing these SWMPs. Our team members actively collaborate with City Council Members, Board of Directors, and staff members to develop resourceful and cost effective best management practices. Each SWMP is created independently to meet the specific needs of the MS4.

For additional information visit the TCEQ website:

If you would like to stay informed about these updates, Speak to a J|C Engineer. For general J|C information, visit us on LinkedIn.


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