The U.S. Environmental Protection Agency (EPA) National Pollution Discharge Elimination System (NPDES) permit requirements for Municipal Separate Storm Sewer Systems (MS4) are the primary regulations that may affect the extent to which storm water BMPs are necessary. The should be consulted to determine the status of the permit and the management plan for the municipality of interest.

In addition to NPDES permit requirements, over the Edwards Aquifer recharge zone, TxDOT is obligated to comply with a memorandum of understanding with the TNRCC that espouses the need for BMPs. Refer to the for details of the most current agreement.