Twin Falls County, ID Outdoor Lighting: Light Trespass & Shielding (2026)

Twin Falls County Code § 8-17-5 sets the siting-permit standards a small animal feeding operation (AFO) must meet before the Planning and Zoning Department will issue approval, and subsection E targets light trespass directly: an applicant must submit evidence, certified by a qualified or licensed professional, that all outdoor lighting will be fully shielded and maintained to eliminate direct glare from properties outside the AFO and to keep direct lighting within the property boundaries. The code defines the standard precisely rather than leaving it to judgment: direct glare is caused when the lamp itself can be seen in the fixture, as opposed to only seeing the light the fixture casts.

To meet the rule, the lighting system must use full cutoff, fully shielded fixtures engineered to control light distribution so that no light is emitted above an angle of eighty five degrees (85 degrees) from a point directly below the fixture, and no fixture may be installed higher than thirty five feet (35'). This sits alongside the section's other siting conditions in subsections A through D and F, which require compliance with state health and human-health regulations, siting that accounts for prevailing climatic conditions, facility design that will not adversely affect neighbors' peaceful enjoyment of their land, and effective buffers against adverse environmental conditions.

Because § 8-17-5 is folded into the permitting process under § 8-17-6, an AFO operator who cannot certify compliant lighting cannot obtain the required siting permit in the first place; the Planning and Zoning Department reviews the certified evidence as part of the application rather than after the fact.