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

C.Maximum Intensity at Property Lines. The maximum light intensity permitted at any residential property line other than a street right-of-way shall prevent light trespass and obtrusive light (a maximum of 0.5 footcandles).D.Security Lighting. Areas requiring security lighting shall comply with the intensity requirements for a low activity area.E.Measurement. Light intensity shall be measured in footcandles on the horizontal plane at five feet above grade level within the site, and on the vertical plane at the property or street-right-of-way boundaries of the site at a height of five feet above grade level.17.403.04.General provisions. The design and illumination standards of this section shall apply to all exterior lighting sources and other light sources visible from the public right-of-way, road easement, or adjacent parcels, except where specifically exempted herein.A.Shielding. Exterior lighting shall be fully shielded and directed downward at a 90-degree angle. Oblique lenses (such as many wall-pack fixtures) are prohibited. All fixtures shall incorporate full cutoff housings, louvers, glare shields, optics, reflectors or other measures to prevent off-site glare and minimize light pollution. Only flat lenses are permitted on shoebox-style light fixtures; sag or protruding lenses are prohibited. See Figure 3 below:

Figure 3: LIGHT FIXTURE ORIENTATION AND SHIELDING Figure 3: LIGHT FIXTURE ORIENTATION AND SHIELDING