Walworth County, WI Outdoor Lighting: Light Trespass & Shielding (2026)

Sec. 74-96, one of the county's Division 8 performance standards, applies across every zoning district and to every use, not just commercial or industrial ones. The rule is written as a flat boundary test: if glare or heat from an activity is visible or measurable at the boundaries of the lot on which the principal use is located, the use is out of compliance, regardless of intent or how the light is generated. Where an operation is inherently glare- or heat-intensive, the code doesn't offer a lesser fix like partial shielding; it requires the activity to be conducted within a completely enclosed building.

A separate, broader duty covers ordinary exposed light fixtures, which shall be shielded so as not to be visible outside their premises, a standard that reaches yard lights, security lighting and business signage lighting alike, not only industrial glare sources. Sec. 74-96 works alongside the county's sign-illumination rules in Sec. cutoff for lit signs near residential zones, and its noise and vibration standards in the same Division 8, showing the same boundary-based approach the county uses for nuisance-type impacts generally. There's no separate lumen, foot-candle or fixture-height number in Sec. 74-96 itself; the test is whether the glare, heat or light crosses the lot line.