Ontario, CA Landscaping Rules: Composting (2026)
Key Facts
- Allowed materials
- Yard trimmings, wood ash, veggie scraps
- Excluded
- Household refuse, animal wastes
- Max size
- 5 ft high x 5 ft wide x 5 ft long
- Placement
- Rear/side yard, hidden from street
- Setback
- 5 ft from property line, or solid wall
- Fire risk override
- Banned where Fire Dept. flags hazard
Summary
Ontario Municipal Code Section 6-3.501 lets residents compost yard trimmings and vegetable scraps at home, provided the pile sits in the rear or side yard, out of street view, capped at five feet in every dimension, at least five feet from the property line, and kept free of odor, rodents, insects, and runoff onto neighboring land.
Sec. 6-3.501. Backyard residential composting.
(a) Notwithstanding any other provision of this chapter, residents are encouraged to compost green wastes, including grass clippings, leaves, plant trimmings, wood ashes and vegetable kitchen scraps (but not including other household refuse or animal wastes). The following conditions regarding composting must be met:
(1) Compost piles or containers are located in the rear or side yard, not visible from a public street, and no greater than five (5) feet in height;
(2) The compost piles or containers are at least five (5) feet from the property line or separated from adjacent property by a solid wall;
(4) The maximum size of any pile or container is five (5) feet in height by five (5) feet in width by five (5) feet in length;
(c) No composting shall be permitted at any location that is determined to be a fire hazard by the City's Fire Department.
Official source re-checked September 7, 2026: no newer edition of the code had been published (publisher’s edition: 2026 S-32: Current through Ordinance 3338, passed 7-21-2026).
Full Breakdown
501(a) encourages composting grass clippings, leaves, plant trimmings, wood ash, and vegetable kitchen scraps, but excludes other household refuse or animal wastes, and imposes six conditions: the pile must sit in the rear or side yard out of view from the street; it must be capped at five feet in height; it must sit at least five feet from the property line or be separated from the neighboring property by a solid wall; it must not generate an offensive odor or harbor rodents; it must be capped at five feet in height by five feet in width by five feet in length overall; it must be enclosed, screened, or otherwise managed to minimize insects or pests; and it must not let surface run-off or leachate cross onto another property.
Subsection (b) lets the Administrator authorize a publicly visible composting demonstration area at a city park or facility for educational purposes. Subsection (c) bars composting entirely at any location the Fire Department determines to be a fire hazard, giving the department veto power over backyard piles in high-risk areas of the city.
Violations & Fines
The code does not set out a stand-alone fine schedule within Section 6-3.501 itself; a pile that violates the size, placement, odor, pest, or runoff conditions, or that sits at a location the Fire Department has flagged as a fire hazard, falls outside the composting authorization and can be treated as a violation of the surrounding Integrated Solid Waste Management chapter's general enforcement provisions.
Frequently Asked Questions
Can I compost in my backyard in Ontario, CA?
How big can a backyard compost pile be in Ontario?
Can animal waste go in a backyard compost pile?
Sources & Official References
Other rules in Ontario
California rules heatmap·Compare Ontario to another location·View the California landscaping rules overview
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Composting in Nearby Cities
How other cities in San Bernardino County handle composting.