Longmont's Environmental Rules: The Rules That Matter
Every city handles environmental rules a little differently. In Longmont, Colorado, there are 4 distinct rules that residents and property owners should be aware of. Some are stricter than what neighboring cities enforce, and others are more relaxed. Here is what you need to know.
Erosion Control
Construction disturbing one acre or more in Longmont requires a stormwater construction activity permit, with a site plan showing erosion and sediment control measures, before any grading or dirt work begins.
Key details: Permit trigger: 1+ acre disturbed. Phased projects: Also count toward the 1-acre trigger. Site plan content: Erosion control plan required. Permit term: Two years.
Starting disturbance without the required permit is unlawful under § 14.26.120 and is enforced the same as any chapter 14.26 violation: a strict-liability offense under § 14.26.160 with fines up to $999 or jail up to 180 days, plus civil penalties up to $500 per day under § 14.26.210.
This is one of the stricter rules in Longmont's municipal code. If you are unsure whether your situation complies, it is worth checking with the city before proceeding.
Flood Elevation Requirements
Longmont requires new and substantially improved residential structures in mapped flood zones to elevate the lowest floor one foot above the base flood elevation, certified by a licensed engineer or surveyor.
Key details: Freeboard: 1 foot above base flood elevation. Applies to: New construction & substantial improvements. Certification: PE, architect, or land surveyor. Nonresidential option: Floodproof to same elevation. Filed with: Floodplain administrator.
Completing or occupying a structure without the required elevation certification violates § 20.16.060, treated as a separate daily offense and public nuisance enforceable by the city attorney.
Stormwater Management
Longmont bans any non-stormwater discharge into its municipal storm sewer system, covering hazardous chemicals, construction runoff and other pollutants, with narrow listed exemptions and daily civil penalties for violations.
Key details: Discharge rule: MS4 ban, few exemptions. Reporting: Report hazardous release within 24 hrs. Criminal penalty: Up to $999 fine, 180 days jail. Civil penalty: Up to $500 per day.
Violating § 14.26.050 is a strict-liability offense under § 14.26.160, punishable by a fine up to $999 or up to 180 days imprisonment per day of violation, plus a separate civil penalty of up to $500 per day under § 14.26.210.
This is one of the stricter rules in Longmont's municipal code. If you are unsure whether your situation complies, it is worth checking with the city before proceeding.
Flood Zones
Longmont Municipal Code section 20.12.030 requires a floodplain development permit before any building, fill, or land-use change proceeds within a special flood hazard area. The director of public works and natural resources serves as floodplain administrator, reviewing applications and enforcing standards that track National Flood Insurance Program minimums. Violators face daily fines under chapter 1.12 and nuisance injunctions, while property owners keep a variance and judicial-review path through the board of adjustment.
Key details: Permit trigger: Any development in special flood hazard area. Administrator: Director of public works and natural resources. Penalty: Separate offense per day, chapter 1.12. Substantial improvement threshold: 50% of pre-improvement market value. RV exemption: On site under 180 consecutive days.
Section 20.16.060 makes it unlawful to construct, locate, extend, convert, or alter any structure or land in the special flood hazard area without full compliance with title 20. Each day the violation continues is a separate offense punishable under chapter 1.12. The city also treats any violation as a public nuisance the city attorney may ask a court to enjoin, on top of the criminal penalty, and the code preserves any other lawful legal or equitable relief the city may pursue.
The Bottom Line
Longmont is tougher than many cities when it comes to environmental rules. Out of the 4 rules covered here, 2 are rated strict. If you are a homeowner, renter, or business owner in Longmont, take the time to understand these requirements before they become a problem. Most violations come with fines, and some repeat violations can escalate.
These rules come from Longmont's publicly available municipal code. For complete penalty schedules, exemption details, and answers to common questions, see the individual ordinance pages throughout this guide.