Ask the Expert, Special Topics in Environmental Management

Does My Site Have Any Post-construction Stormwater Regulations?

Q. How do I know if my site has any post-construction stormwater regulations?

A. You will need to look closely at your permit in your state. There should be some indication if you have post-construction stormwater requirements. The site requirements, if any, could be found within the stormwater pollution prevention plan, or SWPPP requirements. For example, the construction stormwater permit may say something along the lines of “the SWPPP must include a description of any on-site infiltration installed as a means to manage stormwater permanently on site.”

Construction stormwater permit requirements end once the site is stabilized and a Notice of Termination is submitted to the state. If temporary stormwater sediment and erosion controls are installed, in most states, these end when the construction stormwater permit is terminated. However, if permanent post-construction stormwater infrastructure was installed on site, the property owner must continue to operate and maintain this infrastructure. Therefore, it is important to know what post-construction stormwater infrastructure is installed and whether there are any ongoing Best Management Practices (BMPs) to operate, maintain, and keep the infrastructure in working condition.

Certain municipalities that have to abide by their Small Municipal Separate Storm Sewer Systems (MS4) permits may have additional post-construction stormwater requirements. Also, there could be local ordinances that a site owner may need to comply with even after construction is complete. Therefore, you should check your site’s location and see if an MS4 permit is needed from the town or city. You should also check with your local government for any zoning or property ordinances that need to be followed.