An "agricultural building" is defined as a structure designed and constructed to house farm implements, hay, grain, poultry, livestock, or other horticultural products. Said structure shall not be a place of human habitation or a place of employment where agricultural products are processed, treated or packaged, nor shall it be a place used by the public.

A structure constructed for any other use is not an agricultural building, and must be formally permitted.

Examples of structures which are NOT agricultural buildings, and which are subject to the permitting process:

• Carports to park private vehicles.
• Shops for repair of any type of machinery, wood shops, crafts shops, etc.
• Private garages.
• Storage Buildings (other than for hay, farm equipment or farm animals)

RCW 18008410(6) – A building permit shall not be required for an agricultural building, aggregate, less than 4,000 square feet of construction.