Legal Authorities

The 2016 MS4 general permit requires municipalities to pass several 'legal authorities' which could be ordinances, bylaws, regulations, standard conditions of approval or other appropriate legal authorities. Generally, the three legal authorities in the permit are: to prohibit and eliminate illicit discharges, to require low impact development be considered before other practices for managing stormwater runoff, and to require and inspect stormwater runoff control practices at construction sites.

The examples we provide below don't substitute for real legal advice! Please be sure to consult your legal expert or town attorney.


Although the 2004 MS4 general permit previously required towns to establish the legal authority to prohibit illicit discharges to the stormwater system, additional requirements were added to the updated permit. We modified a model IDDE ordinance developed by the EPA to reflect the new requirements of the CT general MS4 permit. The example CT ordinance is available for download here. If you already have an IDDE ordinance and just want to know what the new permit requires for IDDE legal authorities, you can refer to this outline of the requirements.