Do you need a permit for a shed in California? Often not for the building permit, if the shed is small, one story, detached and has no wiring or plumbing. But skipping the building permit doesn't mean skipping the rules. Zoning setbacks, height limits, lot coverage, overlays and easements still apply, even when no building permit is needed.
This guide explains the state permit exemption, what it leaves out, and how Palo Alto, Cupertino, San Mateo and Oakland handle sheds, arbors, decks and other small backyard structures, based on official pages read in November 2026. Rules change and cities can amend the state code locally, so confirm with your own building and planning departments before you order a kit.
The state rule: one story, detached, 120 square feet
The California Residential Code is Part 2.5 of Title 24. The California Building Standards Commission says the 2025 edition of the state building standards code took effect January 1, 2026. In the State Fire Marshal's proposed rulemaking text for the 2025 Residential Code, posted on the Commission's site (not the final published code), section R105.2 lists work that doesn't need a permit, and its first building item reads:
"Other than storm shelters, one-story detached accessory structures, provided that the floor area does not exceed 120 square feet (11.15 m2)."
Palo Alto has its own current wording. Palo Alto Municipal Code section 16.04.110 (Ordinance 5674, 2025), which section 16.06.040 applies to houses, says an exemption doesn't authorize work that breaks the code or other city laws, and then exempts, among other items: one-story detached accessory structures used as tool and storage sheds, playhouses and similar uses, up to 120 square feet, which may still be regulated by section 710A; wood fences up to 7 feet, or concrete or masonry walls up to 4 feet, when not subject to specific Palo Alto planning and zoning rules; retaining walls up to 4 feet from the bottom of the footing, unless they support a surcharge; and wood decks up to 30 inches above grade that aren't attached to a structure or serving any part of the means of egress. That is the code as posted when we read it on November 6, 2026.
The same section opens with the line owners should read first: an exemption from permit "shall not be deemed to grant authorization for any work to be done in any manner in violation of the provisions of this code or any other laws or ordinances of this jurisdiction." In other words, a small shed still has to meet the code and the city's zoning.
The rulemaking text adds that exempt accessory structures may still be regulated by Part 7, the California Wildland-Urban Interface Code. If your house is on a hillside lot in a wildland-urban interface area, read our guide to wildfire home hardening for hillside mid-century homes before you place a shed near the house.
What the exemption doesn't cover
Read the 120-square-foot rule narrowly. As of November 2026, the official pages we checked point to these limits:
Wiring, plumbing or mechanical work. Palo Alto's "Work Exempt from Permit" handout (revised May 2015, citing the 2013 codes) says any electrical, plumbing or mechanical work in an exempt shed requires a permit. Oakland's page also requires a building permit when mechanical, electrical or plumbing work is involved.
Attached structures. The state item quoted above covers only detached structures. Palo Alto's 2015 handout required a permit for an arbor attached to the house, whatever its size.
Anything over 120 square feet. San Mateo says a building permit is required for any storage shed or accessory building over 120 square feet. Oakland says the same.
Zoning. Cupertino says sheds of 120 square feet or less don't need a building permit "but must meet accessory structure ordinance requirements." Oakland says zoning review and a building permit are required for most new accessory structures.
Palo Alto's 2015 handout also warns that when work that needs a permit starts without one, an added penalty fee equal to the permit fee is charged.
Pergolas, arbors, decks and other small structures
A pergola or arbor isn't a shed, and neither the state item nor Palo Alto's code section quoted above names them. Palo Alto's older "Work Exempt from Permit" handout (May 2015, citing the 2013 codes) required a permit for a free-standing arbor over 120 square feet or any arbor attached to the house, and pointed to the zoning code for setback and height limits. Confirm the current rule with the city.
Fences have their own height rules in each city. Fence height, cost sharing and neighbor notice are covered in our guide to the good neighbor fence law in California.
Zoning still applies: setbacks, height and coverage
Where a shed or pergola can go is a zoning question, and it varies by city. Here is what the official pages we read say, as of November 2026.
Cupertino
Cupertino's planning page lists sheds, play structures, covered and uncovered decks and patios, gazebos, arbors and air conditioning units as accessory structures. Its rules include:
All accessory buildings and structures count toward lot coverage, and maximum lot coverage is 30 percent of the usable rear yard.
All enclosed accessory buildings and structures count toward floor area ratio.
Detached accessory structures must be at least five feet from the main house.
Small, portable storage sheds under 6 feet tall, not attached to the building and without a permanent foundation or pad, may be closer than five feet to the house but not closer than 3 feet to any property line.
Front yard setback for detached accessory structures: 20 feet in residential zones and 30 feet in agricultural zones. Street side setback: 15 feet, or 20 feet next to a key lot.
Play structures have their own setback rules.
San Mateo
The City of San Mateo's accessory buildings page says a building permit isn't required for accessory buildings under 120 square feet. Accessory buildings aren't allowed in required front yard setbacks or in side yards in the front two-thirds of the lot, or in required street side yard setbacks on corner lots. In the rear third of the lot they're allowed in side or rear yards and can go right up to the property line, but those in setback areas there face strict height limits; the page refers height and lot coverage questions to the Planning Division. None may be built in a recorded easement without written approval from the agency with jurisdiction over the easement.
Oakland
Oakland's page says one structure under 120 square feet per property is generally permitted outright and doesn't count toward lot coverage; a building permit is needed above 120 square feet or with mechanical, electrical or plumbing work, and the page adds that zoning review is required. The maximum height is generally 15 feet. Side and rear setbacks may be waived under Planning Code section 17.108.130(K) if the whole structure is within 35 feet of the rear lot line, wall height is at most 9 feet and ceiling height at most 12 feet at the peak, at least half the rear yard stays open, and there is no bedroom or full bathroom.
Other cities
If you're in Sunnyvale, Mountain View, San Jose or another city, ask the permit center or planning counter for its accessory structure rules before you build.
Mid-century lots: overlays, easements and the permit record
Some Bay Area neighborhoods sit under a single-story overlay, which adds its own zoning limits; see our guide to single-story overlay districts. Easements matter too: San Mateo bars accessory buildings from recorded easements without written approval from the agency with jurisdiction, and Palo Alto's 2015 handout said a fence in a public utility easement needs an encroachment permit from Public Works. Find out where any recorded easements on your lot run before you pick a spot.
If you're buying, a shed that was exempt won't have a building permit on file. But San Mateo and Oakland require a building permit for a shed over 120 square feet, and Oakland and Palo Alto's 2015 handout require one for wiring or plumbing, so ask about any shed like that. Our guide on how to check permit history walks through the search.
This is general information as of November 2026, not legal advice. Codes and city rules change, so check with your city's building and planning departments, a licensed contractor or an attorney before you build.
Frequently asked questions
Do I need a permit for a 10 by 12 shed in California?
A 10 by 12 shed has 120 square feet of floor area, which doesn't exceed the limit for a one-story detached accessory structure in the rulemaking text for the 2025 code, so it often doesn't need a building permit. San Mateo and Oakland word their cutoff as "less than 120" square feet, so confirm a shed right at 120 with your city. It still has to meet zoning, and Oakland and Palo Alto's 2015 handout require a permit for wiring or plumbing.
Do I need a permit for a pergola?
It depends on the city and the design. Palo Alto's 2015 handout required a permit for a free-standing arbor over 120 square feet or any arbor attached to the house, and Cupertino treats arbors and gazebos as accessory structures under its ordinance. Ask your building department.
Can a small shed go right on the property line?
It depends on the city and where on the lot. San Mateo allows accessory buildings right up to the property line in side or rear yards in the rear third of the lot, with strict height limits in setback areas, but not in front yard setbacks or side yards in the front two-thirds. Cupertino keeps small portable sheds at least 3 feet from any property line.
Related reading
Hire a Licensed Contractor in California: Mid-Century Remodel Guide
Tree Removal Permit in Palo Alto and Nearby Cities Before a Remodel
EV Charger Permit in California: A Guide for Mid-Century Homes
Shared Driveway Easement in California: Utility and Access Easements
More guides on this topic: Owning & Renovating a Mid-Century Modern Home
Planning a backyard project on a mid-century home you own or want to buy? Call or text the Boyenga Team at Compass at (408) 373-1660 or (650) 383-8606, or contact the Boyenga Team to talk it through.
