Light Trespass, BUG Ratings & Municipal Zoning Compliance
Light trespass is light that leaves your property, and controlling it — with BUG-rated fixtures, full-cutoff optics, correct aiming, and curfew controls — is what wins municipal zoning approval and keeps neighbors out of your inbox. For many field projects, zoning is the real gate, and a design that can demonstrate compliance on paper is what gets it through.
This reference covers what zoning cares about, how BUG ratings work, and how to design for compliance.
What zoning cares about
Ordinances increasingly limit how much light crosses a property line (often a vertical-illuminance limit at the boundary) and how much escapes upward (sky glow). Many adopt the Model Lighting Ordinance. The consequence of ignoring this is real: a field that floods adjacent homes can be denied a permit or forced to shut off after complaints. Zoning compliance is a design requirement, not a courtesy.
BUG ratings
| Component | Controls |
|---|---|
| B — Backlight | Light cast behind the fixture (toward property lines) |
| U — Uplight | Light above horizontal (sky glow) |
| G — Glare | High-angle light toward eyes off-site |
The BUG rating (Backlight–Uplight–Glare), defined in IES TM-15, classifies a fixture's distribution into those three components. Lower numbers in the relevant directions indicate better control, so specifying appropriate BUG-rated, full-cutoff fixtures is a direct compliance lever a reviewer can verify objectively.
Designing for compliance
The decisive deliverable is a photometric study that models illuminance at the property line on a spill grid, demonstrating compliance before installation — the document that supports approval. Full-cutoff optics, aiming, shielding, mounting height, and warmer CCT all reduce trespass, and curfew or scheduling controls are often a condition of approval, made automatic and auditable by smart controls. Duvon designs to light-trespass and dark-sky targets and documents the spill for zoning.
Frequently asked questions
What is light trespass and why does zoning care?
Light that leaves your property. Ordinances limit property-line spill and uplight; a field that floods neighbors can be denied a permit or forced to shut off.
What is a BUG rating?
Backlight–Uplight–Glare, defined in IES TM-15 — it classifies a fixture's distribution, with lower numbers indicating better control.
How do you design for zoning compliance?
Model property-line illuminance on a spill grid before installation, using full-cutoff, BUG-rated fixtures, aiming, shielding, and curfew controls.
Are curfew controls required?
Frequently — for fields near homes, an automatic shutoff is often a condition of approval, which smart controls make automatic and auditable.
Does controlling trespass reduce field light?
No — the same optics keep light on the field, so good control improves on-field performance while satisfying zoning.
Request a free certified spill- and zoning-compliant design. Get it at duvonlighting.com/free-quote.