Light Trespass: Ontario vs Rialto
How do light trespass rules compare between Ontario, CA and Rialto, CA?
Ontario has fewer restrictions than Rialto.
Ontario, CA
San Bernardino County
Ontario treats light shining onto neighboring property as a public nuisance under OMC Chapter 30 and zoning Chapter 9, with a typical 0.5 footcandle limit at any residential property line and Code Enforcement response.
View full Ontario rules →Rialto, CA
San Bernardino County
Development Code Chapter 83.07 limits glare onto neighboring property. In the Valley Region, lighting may not exceed 0.5 foot-candle at a residential property line (Section 83.07.030). In the Mountain and Desert Regions, the stricter Light Trespass Ordinance caps trespass at 0.1 foot-candle.
View full Rialto rules →Key Facts Comparison
| Fact | Ontario | Rialto |
|---|---|---|
| Line limit | About 0.5 horizontal fc | - |
| Legal basis | OMC Ch 9 / Ch 30 nuisance | - |
| Contact | Code Enforce (909) 395-2025 | - |
| Civil option | Civil Code 3479 | - |
| Valley Region limit | - | 0.5 foot-candle at residential property line |
| Mountain & Desert limit | - | 0.1 foot-candle |
| Measurement | - | Photometer at setback line; not during moonlight |
| Shielding | - | Full shielding to preclude trespass |
| Code sections | - | 83.07.030 (Valley); 83.07.040 (Mountain/Desert) |
Highlighted rows indicate differences between cities.
Ontario FAQ
How do I prove light trespass?
Document with night photos showing the source and spillover, measure with a smartphone light meter at the property line, then file a Code Enforcement complaint.
Can I sue my neighbor for bright lights?
Yes, California Civil Code 3479 allows a private nuisance action for persistent light trespass after other remedies fail.
Rialto FAQ
How much light is my neighbor allowed to cast onto my property?
In the Valley Region, lighting may not cause glare above 0.5 foot-candle at a residential property line (Section 83.07.030). In the Mountain and Desert Regions, the limit is a stricter 0.1 foot-candle under the 2022 Light Trespass Ordinance.
How is light trespass measured?
Section 83.07.030(b) describes a quantitative method using a yardstick placed at the building setback line and a photoelectric photometer following the International Commission on Illumination standard. Measurements are not taken when there is a moon in the night sky.
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