MSR Frequently Asked Questions (FAQs)

What are Model Subdivision Rules (MSRs)?

The MSRs are model ordinances related to the development of residential subdivisions with lots of five acres or fewer for a single family, detached dwelling.  MSRs were created by the legislature in 1989 to help control the proliferation of developments with substandard water supply and sewer services.  The MSRs are limited in scope to the provision of water supply and wastewater treatment services and minimum setbacks to ensure proper operation of those services.

Who is required to adopt MSRs?

MSRs must be adopted and enforced by: (1) any county adjacent to the Texas-Mexico border; (2) any county or city that seeks assistance from the Texas Water Development Board Economically Distressed Areas Program (EDAP) and (3) by any county in which a city, district, authority, or water supply corporation seeks EDAP assistance.

Are MSRs applicable city-wide and county-wide or can they be done on a precinct-by-precinct basis?

MSRs are adopted and enforced throughout the entire city or county. The MSRs, in partnership with the EDAP financial assistance, are designed to mitigate and prevent future substandard residential development throughout the city or county, not just in the economically distressed areas.

Can the city/county delay adopting MSRs until it knows whether the TWDB will approve financial assistance for an EDAP project?

No.  A city or county that applies for financial assistance from the TWDB, is required to adopt MSRs before an application for financial assistance is submitted to the TWDB for consideration.

What must be included in locally-adopted MSRs?

Basic components of the MSRs that must appear on or be attached to final approved plats include:

  • Applies only to residential subdivisions with lots of five acres or fewer;
  • Only one single family detached dwelling per lot (a statement to this effect must be included on the plat);
  • A description of the method for providing adequate water service;
  • A description of the method for providing adequate wastewater service:
    • Connection to an existing public water or sewer system;
    • Creating a new public water or sewer utility that complies with requirements of the Texas Commission on Environmental Quality (TCEQ); or
    • Installing wells that meet public drinking water standards or septic systems that meet on-site sewerage facility requirement;
    • Certification from a licensed professional engineer regarding the method for providing these services;
  • Must state that the water and wastewater facilities will accommodate ultimate development of the tract for a minimum of 30 years.

Adequate setbacks as required by law (county regulations that are more strict control):

  • 10 feet from roads and right-of-ways;
  • 5 feet from adjacent property lines;

Documentation that, if water and wastewater facilities are not built at the time of final plat approval, the developer has executed an agreement with the county or city to construct and install at developer's expense all subdivision improvements required to comply with county regulations and secured by

  • A bond,
  • An irrevocable letter of credit, or
  • An alternative financial guarantee such as a cash deposit; and
  • A detailed cost estimate for those unconstructed water and wastewater facilities necessary to serve each lot; and
  • A construction schedule for each significant element needed to provide adequate water or wastewater facilities.

No land subdivided for residential purposes may be sold or conveyed until the subdivider:

  • Has received approval of a final plat of the tract; and
  • Has filed and recorded a legally approved plat with the county clerk.

How are MSRs enforced?

MSRs are enforced by the adopting county or city and by the office of the Attorney General.  The TWDB reviews plats filed with and approved by the local government (county or city) for evidence of the conditions required by the MSRs as part of its review of applications for EDAP funding.

How does a City/County know whether water and wastewater infrastructure have been built?

City and County can make that determination through the engineer's certification on the Final Engineering Report attached to the plat.  The report will describe whether infrastructure is constructed.  If it has not been constructed, the report is required to detail the costs for the installing the infrastructure and describe the financial guarantee secured by the developer.

If the water and sewer facilities are not constructed, what should a city or county do?

The law requires the subdivision developer to either construct and install the water and wastewater facilities or provide a financial guarantee sufficient to construct the facilities.  Cities and counties must be prepared to take on the responsibility for completing the project using the developer's financial guarantee.

How much should the financial guarantee be?

The final engineering report attached to the final plat should detail the total project costs for installing the water and wastewater infrastructure, but city and county staff should review the cost estimate BEFORE final approval to make sure the guarantee is not less than the total amount needed to serve the subdivision.

When can the financial guarantee from the subdivision developer expire?

The final engineering report should spell out when the subdivision developer expects to complete the water and wastewater infrastructure projects.  The city or county has flexibility to determine the expiration of the letter of credit, but it should be some time AFTER the developer has had an opportunity to complete the infrastructure project.

What institutions may issue letters of credit?

TWDB rules require letters of credit to be issued only by financial institutions having a ratings equivalent to the minimum acceptable rating established under the county's financial institution rating system.  This information is also contained in Paragraph 11 of the Construction Agreement that must be attached to the Final Engineering Report for the plat.

Can a transaction between the subdivision developer and a homeowner/purchaser be closed or completed before the water/wastewater infrastructure is operational?


Can the city/county approve a preliminary plat without all the required details and then approve an amended plat with all the required details later after the infrastructure has been constructed.

No.  The city/county can only consider a final plat with the necessary Final Engineering Report, financial guarantees, etc.