Maximum Shed Size Without a Permit in California: 120 Sq Ft

In California, the maximum shed size without a permit is 120 square feet of floor area, provided the shed is one story, fully detached from any other building, and used for storage or another non-habitable purpose. That threshold comes from the California Building Code and applies statewide, but your city or county almost certainly adds its own conditions on top of it, and a shed that clears the state rule can still run afoul of local zoning, fire, or HOA requirements.

What the 120-Square-Foot Rule Actually Says

California Building Code Section 105.2 exempts from a building permit “one-story detached accessory structures used as tool and storage sheds, playhouses and similar uses, provided the floor area is not greater than 120 square feet.”¹ The same language appears in the California Residential Code at Section R105.2 for properties governed by that code.²

Three conditions are built into the exemption. The shed must be a single story. It must be fully detached from your house and any other structure on the lot. And it must be used for something non-habitable, like tool storage or a playhouse. A shed that shares a wall with the garage, contains a sleeping loft, or functions as a guest room does not qualify, no matter how small the footprint.

The state code text does not set a height limit. That surprises most homeowners, because nearly every local jurisdiction adds one. Height caps, roof projection limits, and foundation rules you may have heard about are almost always local additions rather than state law. The exemption also does not authorize you to violate any other provision of the building code or local ordinances; it only removes the requirement for a building permit for the structure itself.¹

How Cities and Counties Tighten the Rule

California jurisdictions adopt the state building code as a floor and then amend it. Those amendments frequently narrow the shed exemption.

Los Angeles County, for instance, exempts one-story detached accessory structures only when the floor area stays under 120 square feet, the height does not exceed 12 feet, and the roof projection is no more than 24 inches.³ Other jurisdictions set lower height caps or require design review in certain overlay zones. Some require a zoning clearance or land-use permit even when the building permit itself is waived, so you may still need to visit the planning counter before you build.

The 2025 edition of the California Building Standards Code (Title 24) takes effect January 1, 2026, and local jurisdictions will adopt their own amendments shortly after.⁴ If you’re planning a project in 2026 or later, confirm the rules you’re reading match the current code cycle.

Fire Hazard Severity Zones

If your parcel sits in a designated Very High Fire Hazard Severity Zone, material and construction requirements can apply regardless of shed size. The state code notes that permit-exempt accessory structures may still be regulated under Section 710A, which covers exterior wildfire exposure.¹ In practice, exterior walls may need to be noncombustible or ignition-resistant, and roofing must meet fire-rating standards.⁵ CAL FIRE also enforces defensible-space clearance zones around all structures, so a shed placed too close to vegetation can create a compliance issue even when no building permit was ever needed.

Historic Districts

Properties within a locally designated historic district face restrictions on color, roofing material, height, and architectural style for any new structure, including a small shed. Those design-review requirements exist independently of the building code and can apply even to structures fully exempt under CBC 105.2.

Setbacks and Easements

Every shed must comply with the setback rules in your local zoning code, regardless of size. Setbacks set minimum distances from property lines, the primary dwelling, and the street. They vary by jurisdiction and by zoning designation, so there’s no single statewide number. A common pattern in California cities is 3 to 5 feet from rear and side property lines for detached accessory structures, though some zones require more.

Recorded easements matter just as much. Utility easements cross many residential lots, and building inside one is a reliable way to create a problem you can’t fix cheaply. If a utility company needs access to what’s under your shed, it can require you to remove the structure at your expense. Pull your property’s title report or plat map and mark every easement before you settle on a location.

The Size Exemption Doesn’t Cover What’s Inside

The 120-square-foot rule exempts the shed itself. It does not exempt any systems you install in it. Electrical, plumbing, and mechanical work each require their own trade permits no matter how small the shed.

Running a single outlet, light fixture, or circuit to the shed requires an electrical permit. A homeowner can pull this permit for their own principal residence, but the work must still pass inspection.⁶
Connecting to water or sewer lines requires a plumbing permit and an inspection before the lines are covered.
Installing heating, cooling, or ventilation equipment triggers a mechanical permit.
Even a small off-grid solar setup on a shed roof typically requires both a building permit for the structural attachment and an electrical permit for the panels, inverter, and wiring. California generally requires permits for grid-connected and off-grid systems alike.

A single application can sometimes cover all trade work for the same structure if you file for everything at once.⁷ Otherwise each permit carries its own fee. Work that gets covered up before an inspector signs off has to be uncovered, which costs exactly what you’d expect.

What Skipping a Required Permit Costs

Building a shed that requires a permit without getting one triggers a set of problems that add up quickly.

Most California jurisdictions charge a retroactive investigation fee when you apply after the fact. In Los Angeles, the permit fee is doubled with a minimum of $400, plus a separate code violation inspection fee, and some jurisdictions charge up to four times the standard cost.⁸
If the shed violates setbacks, exceeds allowable size, or sits in an easement, a retroactive permit may not be available at all, and code enforcement can order removal.
If an inspector notices unpermitted construction in progress, work stops until the situation is resolved, and non-compliance fees accumulate.
Homeowner’s insurance may deny a claim related to an unpermitted structure or refuse to cover damage it causes.
California sellers must disclose known unpermitted work to buyers. Unpermitted structures can derail appraisals, deter lenders, and become a negotiating point that costs far more than the original permit would have.

For a shed that legitimately falls under the 120-square-foot exemption and complies with local setbacks, none of this applies. The risk starts when the shed exceeds the exemption, includes unpermitted trade work, or violates placement rules.

HOA Rules Sit on Top of Everything

If your property is governed by a homeowners association, the CC&Rs almost certainly give the architectural review committee authority over any new structure, including a small shed. HOA rules commonly dictate siding materials, roof style, exterior paint colors, and placement on the lot. They operate independently of the building code and are often stricter. Approval from the county means nothing if your HOA required architectural review you never applied for, and violations can bring fines or a demand to remove or modify the shed. Review the CC&Rs and submit plans to the HOA before you order materials.

Property Tax Consequences

California treats a new shed as new construction, defined as any addition to real property since the last lien date.⁹ The county assessor adds the market value of the shed to your existing assessed value through a supplemental assessment. Under Proposition 13, only the value of the new structure is added; the rest of your property’s assessed value stays put.¹⁰ For a modest storage shed, the added tax is usually small, and the supplemental bill arrives separately from your regular property tax bill.

Practical Checklist Before You Build

Measure the floor area carefully. If the design is even slightly over 120 square feet, the exemption does not apply. Check whether your jurisdiction measures to the interior or exterior wall face.
Call your local building department. Confirm the height limit, setback distances, and whether a zoning clearance is required even for exempt structures.
Check your parcel’s fire hazard status through the CAL FIRE hazard severity zone map to determine whether Section 710A material requirements apply.
Pull your title report or survey and avoid placing any structure within a recorded utility or drainage easement.
Plan utility work separately. If you want electricity in the shed, budget for the electrical permit and inspections from the start.
If your property is in an HOA, submit plans to the architectural review committee before construction begins.
Keep documentation. Even for a permit-exempt shed, receipts, site measurements, and any written confirmation from the building department protect you later during a sale or insurance claim.

1
City of Fullerton. 14.03.040 Amendment to Section 105.2 Work Exempt From Permit
2
City of Lathrop. Work Exempt From Permit CRC R105.2
3
LA County Public Works. Work Exempt From Permits
4
California Department of General Services. 2025 Title 24 California Code Changes
5
Tehama County. Materials and Construction Methods for Exterior Wildfire Exposure
6
LA County Public Works. California Electrical Code – LA County Amendments
7
Cornell Law School. Cal. Code Regs. Tit. 25, 1020.3 – Application Requirements for Permits for Accessory Buildings and Structures and Building Components
8
City of Los Angeles. Report on Penalties Imposed for Unpermitted Remodels, Additions
9
California Legislative Information. California Revenue and Taxation Code 70
10
California State Board of Equalization. New Construction