Do I need a permit to build a deck in California?
Short answer: it depends on size, height, and how it attaches. California's code lets a small, low, freestanding deck skip the permit, but the deck has to clear four specific tests. Miss any one of them and you need a permit.
The four-part test
A deck is exempt from a building permit only if it meets all four of these at once: it is not more than 200 square feet, it is not more than 30 inches above grade at any point, it is not attached to the house, and it does not serve the home's required exit door. All four have to be true. If your deck is bigger, taller, bolted to the house, or it is the deck you step onto from the back door, it needs a permit.
Why attached to the house matters so much
A deck that ties into the house carries its load through a ledger board bolted to your framing. Do that wrong and the deck can pull away from the house, which is exactly how the worst deck collapses happen. That is why an attached deck almost always needs a permit and an inspection, even if it is small. The connection is the dangerous part.
Height and the railing question
Once a deck gets up off the ground, the rules on guards and railings kick in for fall protection. A deck low to the ground is treated differently than one you would get hurt falling off of. If your design is up in the air, expect guard height and baluster spacing to be part of the inspection.
Setbacks and your lot still apply
Like a fence, a deck that is exempt from a building permit can still run into zoning. How close the deck can sit to your property line is a planning rule, separate from the permit. So check the building side and the zoning side before you set footings.
Always check your city or county
The four-part exemption is the statewide default, and it is worth reading carefully because all four parts have to hold. Local departments can be stricter, and the zoning setbacks are local. Confirm with your building and planning departments before you build.
Common questions
When does a deck not need a permit in California?
Only when it meets all four conditions at once: not more than 200 square feet, not more than 30 inches above grade, not attached to the house, and not serving the required exit door. If it misses any one, a permit is required.
Does an attached deck need a permit in California?
Yes, almost always. A deck attached to the house carries its load through a ledger connection to your framing, which is a common failure point, so it needs a permit and an inspection.
Do I need a permit for a ground-level deck?
A low, small, freestanding deck can be exempt if it also stays under 200 square feet and does not serve the required exit door. Check all four parts of the test and confirm with your local building department.