Boulder, CO Environmental Rules: Erosion Control (2026)
Key Facts
- Site inspection fee
- $685 per month until land stabilized
- Permit expiration
- 180 days if work has not started
- 1-acre threshold
- State CDPHE stormwater permit required
- Enforcing section
- B.R.C. 1981 § 11-5-6
- Record retention
- 5 years of SCM maintenance records
Summary
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.
(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 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 construction activities covered by the permit shall be completed by the date approved in the permit. Permits shall expire and be void if the activities authorized by the permit have not commenced within 180 days after its issuance, or if the activities authorized by the permit are suspended or abandoned for a period of 180 days.
Official source re-checked September 7, 2026: no newer edition of the code had been published (publisher’s edition: Municipal Code: Supplement 167 Update 3).
Full Breakdown
Section 11-5-6, "Stormwater Quality Management for Land Development," makes drainage facilities and erosion control a precondition of building in Boulder. Subsection (a) requires every new development or redevelopment to provide reasonably necessary drainage facilities. 13 of the City of Boulder Design and Construction Standards; disturbances under one acre outside a common plan need only an erosion control plan under the same Design and Construction Standards section. Permits expire 180 days after issuance if work has not started, or after a 180-day suspension, though the city manager may grant written extensions of up to 180 days each for justifiable cause.
Control measures for erosion and sediment must be selected, installed, and maintained exactly as the approved permit and Design and Construction Standards specify. Section 4-20-71 charges an erosion control and stormwater management site inspection fee of $685 per month, billed until the land is stabilized under the Design and Construction Standards. Before a building permit issues, Subsection (c) also requires a detailed final drainage report addressing post-construction water quality, and owners of stormwater control measures must inspect them at least annually and keep five years of maintenance records under Subsection (c)(3).
Violations & Fines
Starting construction activities before the erosion control permit issues, or working outside its approved terms, violates Section 11-5-6(b) and (b)(1). The $685-per-month site inspection fee under Section 4-20-71 keeps running until the site is certified stabilized, so delay is costly. The city manager may also inspect the site under Section 11-5-7's search-warrant-backed authority, and failing to maintain required stormwater control measures or keep five years of maintenance records under Subsection (c)(3) is a separate, ongoing violation.
Frequently Asked Questions
Does Boulder require a permit before construction site erosion control work begins?
What triggers the state stormwater permit on top of Boulder's local one?
How long does a Boulder erosion control permit last?
Sources & Official References
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Erosion Control in Nearby Cities
How other cities in Boulder County handle erosion control.