DuPage County, IL Outdoor Lighting: Dark Sky Rules (2026)

Section 37-1010(B), "Light: Exposed Sources of Light," governs every activity or operation that produces light in unincorporated DuPage County, from yard fixtures to commercial site lighting. Direct and indirect illumination measured at the lot line cannot exceed one-half foot-candle where the receiving property is zoned residential, and illumination measured within the lot cannot exceed three foot-candles in nonresidential districts. Beyond the numeric cap, every exposed light source must be shielded so it does not throw harmful glare onto adjacent properties, a road, a road right-of-way or an access easement, and glare is analyzed using the IESNA RP-08-00 American National Standard Practice for Roadway Lighting.

The county amended this section by Ord. No. T-3-12B on April 23, 2013, folding the light standard into the same section that regulates residential noise. 1(J)(12) caps off-street parking lot lighting at three foot-candles at the property line generally, dropping to one-half foot-candle where the lot line abuts or faces a residential use or district, and bars loudspeaker systems at parking facilities absent a County Board ordinance. The Department of Economic Development and Planning enforces both standards through the zoning official, and a site plan or permit application can be rejected or conditioned if proposed fixtures cannot demonstrate compliance with the foot-candle limits at the plan-review stage.