Westminster, CO Environmental Rules: Flood Zones (2026)

S. Under Subsection (A), no development, fill, construction, or alteration on a designated floodplain may cause storage of materials that are "buoyant, flammable, explosive or otherwise potentially injurious to human, animal or plant life," disposal of solid waste, downstream debris hazards, or any obstruction that impairs flow capacity. Subsection (B)(5) bars platting any new residential lot located entirely within the 100-year floodplain, and any partial-floodplain lot must still meet every requirement of the chapter. Subsection (I) establishes the permit itself: it "shall be obtained before construction or development begins within any 100-year floodplain area as established in the FIS," and the application must include elevation certifications, flood-proofing engineering, and, where a watercourse or floodway would be altered, an analysis by a registered professional engineer.

The City reviews applications under Subsection (J) to confirm compliance, check for required federal and state permits such as a 404 permit or FEMA approvals, and, for floodway locations, confirm compliance with the additional floodway standards in Section 11-8-14. Subsection (K) further bars issuing a permit for new construction on land removed from the floodplain by a FEMA LOMR-F unless the lowest floor sits one foot above the prior BFE.