Fires of recreational size are always permitted unless there is a burn ban in effect. Recreational fires are less than 3 feet in diameter and 2 feet high and are for cooking and pleasure only. Residential Burning is permitted, with a burn permit, unless there is a burn ban in effect. 

Burning in Snohomish County is regulated by the Snohomish County Fire Marshal’s Office (for fire danger) and the Puget Sound Clean Air Agency (for air quality)

Snohomish County Fire Marshal Office

Puget Sound Clean Air Agency

No person may cause or allow an outdoor fire in an area where the type of burning involved is prohibited under WAC 173-425-040, or where it requires a permit under WAC 173-425-060(2), unless a permit has been issued and is in effect. In addition, the following general requirements apply to all outdoor burning regulated by this chapter, including any outdoor burning allowed without a permit under WAC 173-425-060(2), unless a specific exception is stated in this section:

(1) Prohibited materials. The following materials may not be burned in any outdoor fire: Garbage, dead animals, asphalt, petroleum products, paints, rubber products, plastics, paper (other than what is necessary to start a fire), cardboard, treated wood, construction/demolition debris, metal, or any substance (other than natural vegetation) that normally releases toxic emissions, dense smoke, or obnoxious odors when burned, except that: (RCW 70.94.775(1) and Attorney General Opinion 1993 #17)

(b) Ecology or a local air authority may allow the limited burning of prohibited materials for other firefighting instruction fires, including those that are exempt from permits under WAC 173-425-060 (2)(f), and other outdoor burning necessary to protect public health and safety. (RCW 70.94.650(7))

(2) Hauled material. No outdoor fire may contain material (other than firewood) that has been hauled from an area where outdoor burning of the material is prohibited under WAC 173-425-040. Any outdoor burning of material hauled from areas where outdoor burning of the material is allowed requires an appropriate permit under WAC 173-425-060(2), and any use of property for this purpose on an on-going basis, must be limited to the types of burning listed in WAC 173-351-200 (5)(b) (criteria for municipal solid waste landfills) and approved in accordance with other laws, including chapter 173-304 WAC (Minimum functional standards for solid waste handling) and chapter 173-400 WAC (General regulations for air pollution sources). (RCW 70.94.745(6))

(3) Curtailments.
(a) No outdoor fire may be ignited in a geographical area where:
(i) Ecology has declared an air pollution episode; (RCW 70.94.775(2) and 70.94.780)
(ii) Ecology or a local air authority has declared impaired air quality; or (RCW 70.94.775(2) and 70.94.780)
(iii) The appropriate fire protection authority has declared a fire danger burn ban, unless that authority grants an exception.

(b) The person responsible for the fire must contact the permitting agency and/or any other designated source for information on the burning conditions for each day.

(4) Unlawful outdoor burning: It is unlawful for any person to cause or allow outdoor burning that causes an emission of smoke or any other air contaminant that is detrimental to the health, safety, or welfare of any person, that causes damage to property or business, or that causes a nuisance. (RCW 70.94.040, 70.94.650(1), and 70.94.780)

(5) Burning in outdoor containers. Outdoor containers (such as burn barrels and other incinerators not regulated under WAC 173-400-070(1)) used for outdoor burning, must be constructed of concrete or masonry with a completely enclosed combustion chamber and equipped with a permanently attached spark arrester constructed of iron, heavy wire mesh, or other noncombustible material with openings not larger than one-half inch, and they may only be used in compliance with this chapter.

(6) Other general requirements:
(a) A person capable of extinguishing the fire must attend it at all times, and the fire must be extinguished before leaving it.
(b) No fires are to be within fifty feet of structures.
(c) Permission from a landowner, or owner’s designated representative, must be obtained before starting an outdoor fire.

Land Clearing Burning is illegal in WA State. WAC 173-425-030 defines land clearing burning as: (9) “Land clearing burning” means outdoor burning of trees, stumps, shrubbery, or other natural vegetation from land clearing projects (i.e., projects that clear the land surface so it can be developed, used for a different purpose, or left unused). (RCW 70.94.750(2))