Commission debates dark‑sky style photometric rules, enforcement and grandfathering for new lighting

The commission devoted a lengthy discussion to Article 12, a new, more comprehensive outdoor‑lighting chapter proposed for Westmont’s zoning code. The draft introduces photometric requirements for new development, light‑trespass limits at lot lines (stricter next to residential zones), recommended fixture types (shielded, downcast), and exemptions for detached single‑family homes.

Senior Planner Scott Williams described the change from the existing practice — which in many cases required "0 foot candles at the property line" — to a more nuanced two‑option compliance approach (prescriptive and performance/photometric). He said staff included recommended and not‑recommended fixture graphics to guide applicants. "We're trying to balance introducing regulations, some goals, that the environmental improvement committee has to move towards dark sky," Williams said, while also noting Westmont is not a rural dark‑sky community.

Commissioners raised practical enforcement concerns. Commissioner Peterson and others asked how ambient light would be accounted for in measurements; staff said the draft includes measurement procedures (taking baseline readings with fixtures off to isolate ambient light) and would require calibrated light meters. Commissioners also debated whether to apply the standards to existing lighting and to what extent replacements or retrofits would trigger full compliance. Staff said new fixtures should meet the standard, while replacement of a single head on an existing pole should not necessarily force complete reconfiguration; nonconforming fixture rules and variance options would remain available.

Several commissioners asked for transitional language to avoid immediate hardship for large, established commercial uses — for example, car dealerships with very bright lot lighting. "If a new lamppost in the area didn't have 1 before, yes [staff will require the new code]," Williams said; for replacement of a head, he said, "if they're switching out a picture or something, no." Commissioners pushed staff to define “new” and to include clear provisions for nonconforming existing fixtures, including possible staged compliance timelines.

Public comments that the commission reviewed included a resident recommendation to lower a proposed lumen threshold (from 1,500 lumens to 1,000 lumens) in some contexts. Commissioners asked staff to research other suburban municipal approaches, identify photometric cost/complexity for applicants, and consider a nuisance‑driven enforcement option for resident complaints rather than routine inspections.

Staff agreed to revisit the lighting section with the consultant and return with clarified draft language at the July 23 continuation; no enforcement changes were adopted at the June 25 meeting.