Environmental Rules in Boulder, CO (2026)
5 verified environmental rules for Boulder, Colorado, sourced directly from the municipal code and official government pages.
Verified from official government sources
Stormwater Management
Boulder requires an erosion control permit before any ground-disturbing construction and a city-approved final drainage report before a building permit issues. Property owners fund the Stormwater and Flood Management Utility through fees, and on-site detention facilities must be inspected yearly under Municipal Code Chapter 11-5.
Boulder Stormwater and Drainage Management Rules
Some RestrictionsBoulder Revised Code, B.R.C. 1981, § 11-5-6
(b)Erosion Control Permit Required: No person shall commence construction activities before obtaining an erosion control permit.(1)Compliance With Permit Required: No person shall fail to conduct construction activities consistent with the approved erosion control permit and the requirements of this chapter and the City of Boulder Design and Construction Standards.(3)Expiration: All constructio...
Erosion Control
Before breaking ground, Boulder requires an erosion control permit under Section 11-5-6: no one may commence construction activities without one, and disturbing an acre or more triggers a state stormwater discharge permit plus a city stormwater management plan on top of the local erosion control plan.
Boulder Erosion and Sediment Control Permit
Some RestrictionsB.R.C. 1981 § 11-5-6
(a)Drainage Facilities Required: No person engaged in new development or redevelopment shall fail to provide on such property all reasonably necessary drainage facilities to ensure adequate drainage and management of stormwaters and floods falling on or flowing onto the property.(b)Erosion Control Permit Required: No person shall commence construction activities before obtaining an erosion cont...
Flood Zones
No one may build in Boulder's one-hundred-year floodplain without a floodplain development permit under Section 9-3-6. The city maps the regulated area from FEMA's Flood Insurance Rate Map for Boulder County, dated October 24, 2024, and layers on its own conveyance-zone and high-hazard-zone rules.
Boulder Floodplain Development Permit Requirement
Significant RestrictionsBoulder Revised Code §§ 9-3-2(g)(2), 9-3-3(a)(1)
(1)Floodplain Development Permit: Except as specified in Subsection 9-3-6(a), "Activities Exempt from Floodplain Development Permit Requirement," B.R.C. 1981, no development in the one hundred-year floodplain may occur prior to the issuance of a floodplain development permit pursuant to Section 9-3-6, "Floodplain Development Permits," B.R.C. 1981...the city has adopted the areas of special floo...
Defensible Space
Boulder's Wildland Code requires new buildings in mapped wildland-urban interface areas to keep a modified, maintained defensible space around them, and Section 603.2.5 sets specific planting rules for the zone between 5 and 30 feet from the structure. New trees must be approved species spaced at least 10 feet apart, and every existing juniper in that band must come out.
Boulder's Defensible Space Planting Rules
Some RestrictionsBoulder Revised Code § 10-8.5-2(ff) (Wildland Code § 603.2.5)
603.2.5 Fuels planted within defensible space. The following requirements apply to new and existing plants in the area between 5 feet (1.5 m) from the building or structure and the property lot line, but not to exceed 30 feet (9.1 m) in width within the defensible space:(1)For new buildings and new structures:(A)New plants must be plants that are approved for this area within the wildland-urban...
Flood Elevation Requirements
Boulder does not stop at the base flood elevation: Section 9-16-1 defines a "flood protection elevation" that adds two feet of freeboard above the one-hundred-year flood's water surface (or the AE/AO base flood elevation, whichever is higher), and Section 9-3-3 requires new residential structures to elevate their lowest floor to or above that higher line.
Boulder Flood Protection Elevation Freeboard
Some RestrictionsB.R.C. 1981 § 9-16-1 (Flood Protection Elevation); § 9-3-3(a)(17)
Flood protection elevation means: (1)In the one hundred-year floodplain, an elevation of:(A)Two feet above the elevation of the water surface of a one-hundred-year flood as determined pursuant to Sections 9-3-2 through 9-3-8, B.R.C. 1981, or, if no such elevation is determined, two feet above the highest grade adjacent to a structure; or(B)Two feet above the base flood elevation in AE zones or ...
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County ordinances apply to unincorporated areas and may supplement Boulder city rules.
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