Dark Sky Rules: Castro Valley vs Fremont
How do dark sky rules rules compare between Castro Valley, CA and Fremont, CA?
Castro Valley and Fremont have similar restriction levels.
Castro Valley, CA
Alameda County
East Alameda County supports dark sky preservation near Lick Observatory. Title 17 requires shielded full-cutoff fixtures in rural and hillside zones, stricter near the observatory influence area.
View full Castro Valley rules →Fremont, CA
Alameda County
Fremont requires shielded outdoor lighting under zoning standards, with stricter full-cutoff requirements in the Hillside Combining District to protect night skies.
View full Fremont rules →Key Facts Comparison
| Fact | Castro Valley | Fremont |
|---|---|---|
| Observatory context | Lick Observatory influence | - |
| Fixture standard | Full-cutoff, no uplight | - |
| Color temperature | 2700K or lower preferred | - |
| Curfew | Typical 10-11 PM for non-essential | - |
| Stricter in | Rural and hillside zones | - |
| Shielding | - | Required |
| Commercial | - | Full-cutoff IESNA |
| Hillside | - | Dark sky standards |
| Residential Exempt | - | Under 1,000 lumens |
| Contact | - | (510) 494-4455 |
Highlighted rows indicate differences between cities.
Castro Valley FAQ
Does Alameda County require dark sky lighting everywhere?
No. Urban areas like Oakland and Hayward have less restrictive standards. Rural unincorporated areas near Sunol and Livermore have enhanced dark sky rules due to Lick Observatory proximity.
Are holiday lights allowed?
Yes, seasonal decorative lighting is typically exempt, though most dark sky ordinances encourage turning decorative lights off by 11 PM.
Fremont FAQ
Can I install bright security floodlights?
Yes, but fixtures must be shielded and aimed at your own property, not onto neighbors or the street.
Are string lights allowed in my backyard?
Yes, decorative low-lumen lights are exempt; keep intensity modest to avoid light trespass complaints.
Compare other topics
See how Castro Valley and Fremont compare on other ordinance categories.
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