Backyard ADUs – size, height and permits
Accessory dwelling unit basics: typical size and height limits, setbacks, utilities and when a backyard studio becomes an ADU.
Reading time about 5 minutes
Typical ADU limits
Many states now encourage ADUs. California, for example, requires cities to allow detached ADUs of at least 800 sq ft with 4 ft side and rear setbacks.
Studio or ADU?
A small shed or office without plumbing may be an exempt accessory structure (often under 120–200 sq ft). Add a kitchen and bathroom for living and it becomes an ADU that needs a building permit, utility connections and inspections.
Frequently asked questions
Can I rent out an ADU?
Usually yes once it is permitted, but some cities limit short-term rentals or require owner occupancy.
Codes and zoning vary by state, county and city. Always check with your local building department and HOA before you build.