Lot Coverage Limits: Ontario vs Rialto
How do lot coverage limits rules compare between Ontario, CA and Rialto, CA?
Ontario and Rialto have similar restriction levels.
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 →Rialto, CA
San Bernardino County
San Bernardino County limits maximum lot coverage by buildings to 40-50% in residential zones, 20-30% in rural zones, with impervious surface limits on hillsides and near watercourses.
View full Rialto rules →Key Facts Comparison
| Fact | Ontario | Rialto |
|---|---|---|
| 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.
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.
Rialto FAQ
Compare other topics
See how Ontario and Rialto compare on other ordinance categories.
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