Grading & Drainage: Ontario vs Rialto
How do grading & drainage rules compare between Ontario, CA and Rialto, CA?
Rialto has fewer restrictions than Ontario.
Ontario, CA
San Bernardino County
Ontario requires a grading permit under OMC Title 6 for any earthwork over 50 cubic yards or cuts and fills deeper than 3 feet, with geotechnical review for projects over 500 cubic yards.
View full Ontario rules →Rialto, CA
San Bernardino County
Rialto regulates grading and on-site drainage through Title 15 (Buildings and Construction), which adopts California Building Code Appendix J. A grading permit is generally required for any earthwork exceeding 50 cubic yards, any cut or fill over 5 feet, or work that alters established drainage patterns. Drainage must convey runoff to an approved point of disposal without discharging concentrated flows onto adjacent property.
View full Rialto rules →Key Facts Comparison
| Fact | Ontario | Rialto |
|---|---|---|
| Permit trigger | 50 cu yd or 3 ft deep | - |
| Geotech | Over 500 cu yd | Soils report per CBC §1803 typical |
| Dust rule | SCAQMD Rule 403 | - |
| Retaining wall | Permit over 4 ft | - |
| Permit threshold | - | 50 cu yd or 5 ft cut/fill; any altered drainage |
| Code basis | - | CBC Appendix J via Rialto Title 15 |
| Engineering | - | Drainage plan stamped by CA civil engineer |
| Discharge rule | - | No concentrated runoff onto adjacent property |
Highlighted rows indicate differences between cities.
Ontario FAQ
Do I need a permit to add a foot of fill to my yard?
Only if the total volume exceeds 50 cubic yards or you create a slope steeper than 3:1 near a property line.
What is SCAQMD Rule 403?
It is the South Coast Air Quality Management District rule requiring dust control on graded sites via watering, covers, or soil binders.
Rialto FAQ
Do I need a permit to level my backyard?
Yes if the earthwork exceeds 50 cubic yards, cuts/fills exceed 5 feet, or you alter how stormwater flows to neighboring properties. Minor leveling under those thresholds may not need a permit but still must comply with drainage rules.
Can I direct gutter downspouts toward my neighbor's yard?
No. Concentrating roof or graded runoff onto adjacent property is prohibited under Cal. Civil Code §3479 (nuisance) and Rialto's drainage code. Use splash blocks, dispersal trenches, or connect to an approved storm drain.
How long does a grading permit take in Rialto?
Plan check for a residential drainage/grading permit typically runs 4-6 weeks depending on geotechnical review. Hillside or flood-zone projects take longer due to additional reviews.
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