County updates exterior lighting code, adds protections for natural areas and extends rules to new single‑family and duplex construction

The Larimer County Board of County Commissioners approved technical updates to Article 4.10 of the Land Use Code governing exterior lighting, adding modern technical standards, environmental protections near publicly protected open spaces, and clarifying lighting-plan submittal requirements. The board voted 3-0 to adopt the revisions and, during deliberation, directed staff to apply the standards to new single‑family and duplex residential construction; the effective date for the code changes is Feb. 13, 2025.

Principal Planner Cassidy Fiore told commissioners the update is intended to protect dark skies, reduce light trespass and glare, conserve energy, and protect natural features and wildlife (including migratory corridors). Key provisions include reducing allowed light trespass adjacent to publicly protected open spaces, sensitive habitats and waterways, encouraging lower correlated color temperature (CCT) lighting next to protected spaces, requiring lighting plans for applicable developments, and updating exemptions (emergency lighting, traffic control, FAA-governed lighting, holiday lighting). The update leans on Dark-Sky International and Illuminating Engineering Society best practices and draws on a scan of neighboring jurisdictions.

Staff outlined a two-phase project: Phase 1 is the land use code amendment (adopted by the board); Phase 2 would seek carryover funding to engage a consultant for public education, staff training, a dedicated web page of best practices, and work to better align building-code and land-use-code requirements. Commissioners asked about whether the Article 4 development standards apply to single-family and duplex dwellings; staff advised the Article 4 definition of "development" currently excludes construction of individual single-unit or duplex dwellings, but the board requested the lighting requirements be extended to those residential building permits so new homes will be subject to the updated lighting standards. Commissioners also discussed potential education and incentive work to support retrofits and contracting hardware stores to increase availability of compliant fixtures.

The board approved the amendment (file 24CODE0281) and set the effective date for February 13, 2025. Staff will proceed with online code updates, and Phase 2 contingent funding would include outreach and consultant assistance to align the building code and deliver education and technical resources.