Bay Area remodeling guide

Permits, licenses, and who can do the work.

Name: Remodel Carpenters
Price range: $

Before you pick up a hammer or hire anyone, know when your project needs a permit, when it needs a licensed contractor, and when you can legally do it yourself. Here's how it works in San Francisco, Alameda, Contra Costa, Marin, San Mateo, and Santa Clara counties.

PermitNeeded when you change structure, plumbing, electrical, or mechanical systems.

LicenseNeeded for any hired job over $1,000 in labor and materials, or any job that needs a permit.

Do it yourselfOwners can do most work on their own property, with permits where required.

Understanding permits

Why permits exist

Permits make sure construction and remodeling work meets local building codes, zoning rules, and safety standards. The California Building Standards Code sets the baseline statewide, and each county and city adds its own rules on top. As a general rule, any project that alters a building's structure or its electrical, plumbing, or mechanical systems needs a permit. Skipping one can lead to fines, delays, orders to redo work, and complications when you sell.

Large projects that need permits

New construction: a new home, an addition, or an accessory dwelling unit (ADU).
Structural changes: removing or altering load-bearing walls, foundation work, adding a story.
Major kitchen and bath remodels: relocating fixtures, upgrading panels, or changing the floor plan.
Exterior work: decks, balconies, exterior stairs, taller fences, and retaining walls over 4 feet.

Smaller projects that often need permits

Electrical: new circuits and outlets, panel upgrades, moving wiring.
Plumbing: adding or relocating sinks, toilets, or showers; replacing water heaters.
Mechanical: installing or replacing HVAC, laundry hookups, or ventilation.
Windows and doors: cutting new openings. Like-for-like replacements in existing frames are sometimes exempt.

Usually no permit needed

Cosmetic work: painting, wallpaper, and refinishing floors.
Like-for-like fixture swaps: replacing a faucet or fixture without altering valves, traps, or wiring.
Small accessory structures: sheds under a size and height limit (in San Francisco, roughly 100 square feet and 8 feet tall).
Lower fences: fences under the local height limit at rear and side lot lines.
Minor repairs: small patches and repairs that don't alter systems or structure.

Exemptions vary by city. San Francisco lists its exemptions in Building Code Section 106A.2. Always confirm with your local building department.

At a glance

Permit, license, or do it yourself?

Project	Permit?	Licensed contractor?	Owner can do it?	Notes
New construction	Yes	YesClass B general contractor, plus licensed electrical and plumbing subs.	YesAs an owner-builder, with permits.	Plans by a licensed architect or engineer; multiple inspections.
Structural changesLoad-bearing walls, additions	Yes	YesGeneral contractor or licensed specialty subs.	YesAs an owner-builder, with permits.	Engineering drawings often required.
Kitchen or bath remodelWith plumbing or electrical	Yes	YesClass B or B-2 remodeler, or licensed specialty subs.	YesAs an owner-builder, with permits.	San Francisco offers online permits for registered contractors.
Electrical workNew outlets, panel upgrades	Yes	YesC-10 electrical contractor.	YesAs an owner-builder, with permits.	Most new wiring needs a permit; simple like-for-like swaps may not.
Plumbing workRelocating fixtures	Yes	YesC-36 plumbing contractor.	YesAs an owner-builder, with permits.	Inspections verify drains, venting, and supply lines.
Mechanical workHVAC, laundry hookups	Yes	YesC-20 HVAC contractor or similar.	YesAs an owner-builder, with permits.	Required for new installations and replacements.
Exterior alterationsDecks, taller fences	Yes	YesGeneral contractor or appropriate specialty license.	YesAs an owner-builder, with permits.	San Francisco may require neighborhood notification.
Cosmetic and minor workPainting, replacing cabinets	No	Over $1,000Required if a hired job exceeds $1,000 in labor and materials.	YesOwners and occupants can do it.	Exempt from permits, not from licensing.
Small accessory structuresSmall sheds	No	Over $1,000Same $1,000 rule for hired work.	Yes	Check local size and height limits.
Window and door replacementIn existing frames	Usually no	Over $1,000Same $1,000 rule for hired work.	Yes	New or enlarged openings need permits.

General guidance for most Bay Area jurisdictions. Requirements vary by city and change over time.

Licensed contractor requirements

When you need a licensed pro

$1,000

California's licensing threshold. Since January 1, 2025, anyone hired for a job worth $1,000 or more in combined labor and materials must hold a license from the Contractors State License Board (CSLB). Below that, the "minor work" exemption only applies if no permit is required, the person works alone, and the job isn't split up to stay under the limit. Unlicensed workers who advertise must say they're not licensed.

BGeneral building: new construction and multi-trade structural work

B-2Residential remodeling: improving existing homes across multiple trades

C-10Electrical

C-36Plumbing

For new construction, or remodels with structural, plumbing, or electrical components, a licensed contractor typically pulls the permits and runs the job. Specialty work is done by contractors with the matching license, such as C-10 for electrical, C-36 for plumbing, or C-20 for HVAC.

The owner-builder option

Ownership: you must be the owner on title. Renters can't pull permits without the owner's authorization.
Responsibility: you're legally responsible for meeting code, and for redoing work that doesn't pass.
Plans: structural, electrical, and plumbing work often needs plans from a licensed architect or engineer.
Help: owner-builders can't hire unlicensed workers for permitted work. Anyone you hire needs a license, or becomes your employee, with the obligations that come with that.

Remodel work, permitted or not

Permitted remodels: a licensed contractor generally pulls the permit and does the work, or the owner does it as an owner-builder.
Cosmetic remodels: no permit is needed, but hired work over $1,000 still requires a license.
Doing it yourself: owners and occupants can do cosmetic work freely, as long as it doesn't touch systems that require permits.

What's at stake

The risks of unpermitted work

Penalty fees, often a multiple of the original permit cost.

Orders to open up, redo, or remove finished work.

Problems at sale, when buyers, lenders, or inspectors find it.

Safety hazards from work nobody inspected.

County by county

Local rules to know

San Francisco

Strict rules shaped by density and historic preservation. The Department of Building Inspection handles permits, and many exterior or expansion projects require neighborhood notification.

Alameda

Permits for most structural, electrical, and plumbing work. Cities like Oakland and Berkeley set their own specific rules.

Contra Costa

Similar to Alameda, with inspections during construction. San Pablo, for example, requires permits for most remodeling and repairs.

Marin

Historic properties may need additional approvals. Pre-application meetings are recommended for unusual projects.

San Mateo

Kitchen and bath permit fees are based on project valuation, including labor and materials. Plans are required for most remodels.

Santa Clara

Strict zoning, with inspections at stages like foundation, framing, and electrical. Historic properties may need heritage commission approval.

Practical tips

Before you start

Research local requirements. Start with your city or county building department's website, such as sfdbi.org in San Francisco or smcgov.org in San Mateo, or the San Francisco Property Information Map.
Verify any contractor's license. Check it on the CSLB website before you hire, and make sure the license class matches the work.
Bring in professionals early. An architect, engineer, or contractor can streamline the permit process on complex projects.
Schedule inspections. For permitted work, inspections at each stage verify the work meets code.
Keep records. Save permits, plans, and inspection sign-offs. You'll want them when you sell.

This guide is general information, not legal advice. Permit and licensing rules vary by city and change often. Confirm requirements with your local building department and the Contractors State License Board before starting work.

Planning a remodel?

Most of what we do is improving what's already there, the kind of work that keeps permitting simple. Send photos and a sentence about the project, and we'll come back with a price within 24 hours.

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