Per the California Residential Code detached accessory structure not exceeding 120 square feet does not require a building permit if there is no plumbing, electrical, and or mechanical equipment. Please note, Sheds and/or Structures under 120 square feet do require a Planning Permit.
A building permit is not required for the following: One-story detached accessory structures used as tool and storage sheds, playhouses, and similar uses, provided the floor area does not exceed 120 square feet (11 square meters).
Storage sheds that are less than 120 square feet and eight feet in height do not require a building permit, but still require Planning Division approval through an over-the-counter application called a Zoning Clearance.
Types of Projects That May Be Exempt From a Building Permit in California Painting. Floor upgrades. Kitchen remodels. Small drywall projects. Common electrical work. Small outbuildings. Bathroom fixes. Fences.
A Residential Accessory permit is required prior to any construction of residential accessory structures greater than 120 square feet. The definition of Accessory Structure is any structure accessory to and incidental to that of the dwelling(s) and that is located on the same lot.