Thornton, CO Fire Regulations: Fire Pits & Backyard Fires (2026)
Fire pit rules in Thornton, CO, also called outdoor burning, recreational fire, or open flame ordinances, cover fuel types, clearances, and when burning is allowed.
Key Facts
- Permit-exempt size
- 3 ft diameter, 2 ft height fuel area or less
- Wood/solid-fuel setback
- 15 feet from any structure
- Gas/propane setback
- 5 feet from burner to structure
- Container material
- metal, concrete or other noncombustible
- Spark screening
- required for wood-burning fires at single-family homes
- Standard (non-exempt) setback
- 50 feet under general open-burning rule
Summary
Thornton lets small contained fire pits, chimineas and outdoor fireplaces skip the Open Burning permit if the fuel area is 3 feet or less in diameter and 2 feet or less in height, but still sets a minimum setback: 15 feet from the house for wood fires and 5 feet for gas or propane fires, under the amended Fire Code Section 307.
307.1.1 Approved open burning. Open burning shall only be conducted for the following purposes or activities:...5.Fires contained by a commercially available chiminea, outdoor fireplace or fire pit, or other approved method having a total fuel area of 3 feet (914 mm) or less in diameter and 2 feet (610 mm) or less in height. 307.3 Location. The location for open burning shall not be less than 50 feet (15,240 mm) from any occupiable structure and appurtenances...Exceptions: 1.The minimum required distance from a structure shall be 15 feet (4,572 mm) where the fuel being burned is wood or other solid fuel and the fire is contained by a commercially available chiminea, outdoor fireplace or fire pit...2.The minimum required distance from a structure to any point of the burner shall be 5 feet (1,524 mm) where the fuel being burned is natural gas or propane and the fire is contained by a commercially available chiminea, outdoor fireplace or fire pit, or other approved method having a burner of 3 feet (914 mm) or less in diameter with a maximum flame height of 2 feet (610 mm).
Official source re-checked September 7, 2026: no newer edition of the code had been published (publisher’s edition: Code of Ordinances: Supplement 65).
Full Breakdown
1(5) lists fires contained by a commercially available chiminea, outdoor fireplace, fire pit or other approved method with a total fuel area of 3 feet or less in diameter and 2 feet or less in height as an approved form of open burning that does not require the same review as a general open-burning permit application. 3, they still carry their own distance rules: a wood or other solid-fuel fire in a compliant chiminea, fire pit or outdoor fireplace must stay at least 15 feet from a structure, while a natural gas or propane fire in a compliant burner of the same size, with a maximum flame height of 2 feet, need only stay 5 feet from a structure measured to any point of the burner.
4 requires the container itself to be built of metal, concrete or other approved noncombustible material, and for wood-burning fires at single-family (Group R-3) properties, all openings in the container must be covered with wire mesh or other screening that prevents sparks and embers from escaping. 5 apply to these fires the same as any other open burning.
Violations & Fines
A fire pit that exceeds the 3-foot diameter or 2-foot height fuel-area limit, or that sits closer to a structure than the 15-foot wood or 5-foot gas/propane setback, loses its exemption and becomes unlawful open burning under Section 307.1, punishable under Section 113.4's reference to the city's general penalty in Section 1-8(a), with each continuing day after notice a separate offense.
Frequently Asked Questions
Do I need a permit for a backyard fire pit in Thornton?
How big can my Thornton fire pit be without a permit?
How far must a propane fire pit sit from my house in Thornton?
What material must a Thornton fire pit be made of?
Sources & Official References
Other rules in Thornton
How Thornton compares: Cities with the Strictest Fire Pit Rules·Compare Thornton to another location·View the Colorado fire regulations overview
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