Can You Get a Permit for a Garage Conversion ADU in California? Here’s What You Need to Know

As housing costs continue to climb and urban space remains limited, garage conversion ADUs (Accessory Dwelling Units) are becoming one of the most popular ways California homeowners are increasing property value, generating passive income, and expanding affordable housing options — all without expanding their home’s footprint.

But can you legally get a permit for a garage conversion ADU in California? The short answer is yes — and it’s easier than ever in 2025. With streamlined ADU laws and zoning updates, the state has made converting an existing garage into a legal living space not only possible but highly encouraged.

Let’s break down everything you need to know.

🏡 What Is a Garage Conversion ADU?

A garage conversion ADU is a type of accessory dwelling unit created by transforming an attached or detached garage into a fully functional living space. These units typically include:

• A bedroom or studio layout

• A bathroom

• A kitchenette or full kitchen

• Utilities (electricity, plumbing, and HVAC)

Garage ADUs are especially appealing in California because they maximize existing structures and often cost less to build than detached or new-construction ADUs.

✅ Can You Get a Permit for a Garage Conversion ADU in California?

Yes — and California law supports it. Thanks to statewide ADU legislation (such as SB 1069, AB 68, and updates through 2025), garage conversions are legal and must be permitted by your local city or county — as long as they meet state-mandated criteria.

California ADU Laws That Support Garage Conversions:

• Local governments must allow garage-to-ADU conversions, even if the garage is detached.

• Parking replacement is NOT required if your property is within ½ mile of public transit.

• Permits must be approved within 60 days of a completed application.

• Cities cannot impose minimum lot size requirements to block ADU projects.

• Fire sprinklers are not required in ADUs if not required in the main home.

📋 Permit Requirements for a Garage ADU in California

To legally convert your garage into an ADU, you’ll need to follow the building code and zoning regulations for your city or county. Here's a general checklist of what most local jurisdictions require:

🔨 Basic Permit Requirements:

• Structural integrity: Foundations, walls, and roofs must meet current code.

• Insulation and drywall upgrades for living space

• Installation of windows and doors for natural light and egress

• Electrical and plumbing systems up to code

• Connection to city sewer or septic system

• Kitchen and bathroom facilities

🏘 Zoning and Planning:

• Must comply with rear and side yard setbacks (often reduced for ADUs)

• Height limits vary by city but typically around 16–20 feet

• Design compatibility with primary residence may be required in some cities

• No HOA can unreasonably restrict ADU development, including conversions

💰 How Much Does It Cost to Convert a Garage Into an ADU in California?

Garage conversion costs in California (as of 2025) typically range from $90,000 to $160,000, depending on the size, location, and condition of the garage. This includes construction, permitting, utility upgrades, and finishes.

However, homeowners may qualify for financial incentives like:

• CalHFA ADU Grants up to $40,000 for pre-construction costs

• Low-interest ADU loans through state-approved lenders

• Waived or reduced impact fees for ADUs under 750 sq ft