On average, homeowners can expect to spend anywhere from $3,000 to $10,000 on permit fees for an ADU project in Riverside County.
In California, the largest structure you can build without a permit is generally a detached accessory structure like a shed, provided it does not exceed 120 square feet and does not involve any plumbing or electrical systems.
One story detached accessory structures used as a tool or storage shed, playhouses and similar uses, provided the floor area does not exceed 120 square feet. Fences not over seven (7) feet high (Approval may be required from the Planning Division for fences located in the front yard setback)
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.
A permit is required before constructing, enlarging, altering, repairing, or demolishing a building or structure or installing or altering any equipment which is regulated by the model codes adopted by the County of Riverside.
Projects that DO NOT need a building permit are simple surface (cosmetic) projects; minor repairs and replacements; and minor site improvements or small structures.
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.