Lot Coverage Limits: Fontana vs Ontario
How do lot coverage limits rules compare between Fontana, CA and Ontario, CA?
Fontana and Ontario have similar restriction levels.
Fontana, CA
San Bernardino County
Fontana FMC Title 17 caps the share of a lot that buildings may occupy. R-1 zones typically allow 40-50 percent coverage. Accessory structures count; state ADU law guarantees an 800 sq ft ADU.
View full Fontana rules →Ontario, CA
San Bernardino County
Ontario single-family lots are limited to about 40 to 50 percent building coverage under OMC Chapter 9, with additional impervious-surface restrictions tied to the San Bernardino County MS4 stormwater permit.
View full Ontario rules →Key Facts Comparison
| Fact | Fontana | Ontario |
|---|---|---|
| Governing Code | FMC Title 17 | - |
| R-1 Typical | 40-50% coverage | - |
| Multi-Family | 50-60% coverage | - |
| ADU Minimum | 800 sq ft guaranteed | - |
| Open Patios | Often excluded | - |
| Coverage max | - | 40-50% single-family |
| Measurement | - | Roofed footprint |
| Stormwater | - | MS4 over 5,000 sq ft |
| ADU exempt | - | Under 800 sq ft (AB 68) |
Highlighted rows indicate differences between cities.
Fontana FAQ
What counts toward lot coverage in Fontana?
Enclosed buildings including the primary home, garages, and sheds generally count. Open patios, pools, and driveways are typically excluded from coverage calculations.
Can an ADU push my lot over coverage limits?
Under California Gov Code 65852.2, Fontana must allow an ADU of at least 800 square feet even if standard lot coverage rules would otherwise block it.
Ontario FAQ
Does my patio cover count toward lot coverage?
Solid-roof patios count; open pergolas without a roof typically do not count toward coverage in Ontario.
Does an ADU count toward my lot coverage?
A detached ADU under 800 sq ft is excluded from lot coverage under California Government Code 65852.2.
Compare other topics
See how Fontana and Ontario compare on other ordinance categories.
Want to add a third city?
Use our full comparison tool to compare up to three cities.
Open Comparison Tool