St. Tammany Parish, LA Environmental Rules: Erosion Control (2026)

Sec. 900-6.9(F) of the Unified Development Code makes every operator of a construction site, whether working on new residential or commercial construction, subdivision development, pool installation, pond excavation or a remodel that alters site drainage, responsible for controlling discharge to the parish's MS4, drainage infrastructure and waterways. Operators must use Best Management Practices selected from the Best Management Practices for Coastal Louisiana Nonpoint Source Pollution Handbook to keep silt, sediment, mud and clay off-site to the maximum extent practicable, and parish permits must be secured before construction starts.

An approved Stormwater Agreement, provided by the parish and signed at building-permit or site-work-permit stage, commits the owner to obtain any required LDEQ permit; subdivisions developed in phases file one at each phase's concept-plan stage. A Construction Stormwater Site Plan covering erosion control, sediment control and receiving-water impacts must accompany the permit application under Sec. 900-6.9(H). During construction, disturbed soil not actively worked must be stabilized within 14 days, BMPs must be self-inspected and repaired before the next storm, and a stabilized construction entrance/exit pad is required to keep mud off public roads. Sites of 5 acres or more (including phases of a larger common plan) need an LDEQ Notice of Intent and full SWPPP; sites between 1 and 5 acres need a SWPPP without an NOI. Capital projects run by parish personnel, life-safety emergency work, grave excavation and ordinary agricultural practices are exempt from the Stormwater Agreement and site-plan requirement, though the owner still must maintain erosion controls.