FEMA flood zone rules in Longmont, CO — also called floodplain regulations or special flood hazard area (SFHA) rules — determine flood insurance requirements and elevation standards for new construction.
Longmont's floodplain regulations are codified in LMC Title 20 (Floodplain Regulations). St. Vrain Creek runs through the heart of the city and produced the catastrophic September 2013 flood that displaced hundreds of residents — making floodplain compliance one of the most active regulatory areas in town. Any construction or development inside a FEMA Special Flood Hazard Area (SFHA) requires a Floodplain Development Permit issued by the city Floodplain Administrator, with a $100 application fee.
LMC Title 20 governs all floodplain activity within Longmont city limits and implements the National Flood Insurance Program for the community. The regulated area is the FEMA Special Flood Hazard Area (SFHA) — the 1% annual chance (100-year) floodplain shown on the current effective Flood Insurance Rate Map (FIRM) or the latest Letter of Map Revision (LOMR). Title 20 defines the 100-year flood as a flood with a recurrence interval that has a one percent chance of being equaled or exceeded in any given year and uses that elevation as the regulatory benchmark for fill, structures, and substantial improvements. Any construction or development — including placement of a manufactured home — in the SFHA requires a Floodplain Development Permit before work begins. Applications are reviewed by the Floodplain Administrator (Monica Bortolini, PE CFM) at the Development Services Center, 385 Kimbark Street, and the application fee is $100. Submittals must show the 100-year floodplain boundary from the current effective FIRM or latest LOMR. Longmont's St. Vrain Creek corridor was remapped after the September 11-15, 2013 flood; CDOT and the Colorado Water Conservation Board re-ran the hydrology, FEMA approved updated FIRM panels in 2015, and a series of LOMRs from the Resilient St. Vrain Project (starting with LOMR #1 downstream of the BNSF railroad south of the creek) have progressively removed restored reaches from the 100-year floodplain. Use the city's online Floodplain Inquiry Map or call Planning & Development Services at (303) 651-8330 to check a specific address against current effective mapping before designing or buying.
Building or filling in the SFHA without a Floodplain Development Permit violates LMC Title 20 and is prosecuted in Longmont Municipal Court at up to $999 and/or 180 days per LMC Title 1 general penalty. The city can issue a Stop Work order, require removal of unpermitted fill or structures, and refuse Certificate of Occupancy. Federal consequences are larger: noncompliant structures jeopardize the entire community's NFIP eligibility, can trigger FEMA Section 1316 denial of flood insurance to the specific property, and can disqualify the owner from federal disaster assistance. Insurance carriers may also refuse or rate-up coverage on unpermitted floodplain construction.
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Longmont, CO
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