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ADU Laws in California: Permits, Requirements, and Selling Options

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New California ADU requirements make it easier than ever to add an Accessory Dwelling Unit to your property. In this guide, you’ll find the basics of 2024 ADU rules, permits, selling options, and tips on choosing ADU builders. If you are looking to get extra rental income, family space, or guest accommodations, this will help you get started.

Can I Build an ADU on My Property?

California allows ADUs on most residential properties, though local regulations can vary. Sacramento, for example, has its own guidelines you’ll need to follow:

  1. Zoning: ADUs are permitted in most residential zones, including single-family and multifamily areas.
  2. Unit size: The maximum size of Detached ADUs is 1,200 square feet, and Attached ADUs can’t be larger than 850 square feet for a studio or one-bedroom unit and 1,000 square feet for a 2+ bedroom unit. Also, no ADU can be more than 50% of the primary residence's size.
  3. Separation: Detached ADUs must be at least 4 feet away from the main dwelling to ensure safety and accessibility.
  4. Setbacks: A 4-foot setback is required from the side and rear property lines.
  5. Height Restrictions: In the R-1 zone, the maximum height is 35 feet.
  6. Front Yard Placement: one ADU that does not exceed 800 square feet is allowed in the front-yard setback area if the lot area in the rear and side yards.
  7. Permits: You'll need a completed application, site and floor plans, structural and utility plans, energy compliance documentation, possibly a soil report and stormwater management plan, fire department and HOA approvals if applicable

If your property meets these requirements, you’re ready to move forward. When choosing a reliable local contractor, look for someone with proven ADU experience, solid reviews, proper licensing, and a clear, itemized cost estimate to avoid surprises.

New California ADU Laws for 2025

  • AB 1033: Homeowners in big cities, including Sacramento, now can sell ADUs separately from the main home as individual condominiums.
  • AB 976: Homeowners can now rent both the main house and the ADU without needing to live there.
  • SB 897: This law allows ADUs to be built up to 18 feet tall in some cases, giving homeowners more freedom in their ADU designs.

Important Updates To Existing California ADU Requirements

Faster Permit Approvals

Cities, including Sacramento, now have to approve ADU permits within 60 days. This means less waiting and quicker project timelines.

More Flexible Size and Placement Rules

Homeowners have greater freedom to design ADUs that fit their property. Setback restrictions from property lines have been reduced, opening up more placement options.

Relaxed Parking Requirements

If your property is near public transportation, you might not need to add extra parking for your ADU. This makes adding an ADU on smaller or busier lots much easier.

Encouragement for Green Building

New ADUs are encouraged to use energy-efficient designs and materials. This can lower utility costs and help make the unit more eco-friendly.

Steps to Get ADU Building Permits in California

Step 1: Gather Your Plans
Get a site plan, ADU floor plans, and utility details together. You might also need a Title 24 energy report.

Step 2: Submit to the City
Bring your documents to your building department for a quick review to ensure your plans fit local rules.

Step 3: Handle Extra Approvals (if needed)
If your property has specific needs—like being in a fire zone—check if extra approvals apply.

Step 4: Get Your Permit
Once approved, you’ll get the permit. Keep it visible on-site while building.

Step 5: Start Building
With your permit, you’re set to begin. Follow the approved plans and stay on top of any required property inspections.

Selling an ADU in California

Step 1: Understand Separate Sale Limitations: Check with your city or county to see if they participate in AB 1033 or any programs that allow separate sales of ADUs.

Step 2: Explore Condo Conversion: Another way to legally sell an ADU separately is legally splitting the main home and the ADU into separate units through city approval.

Step 4: Calculate the Value: Obtain a professional appraisal from a real estate agent that reflects the ADU’s contribution to the property’s overall value to set a competitive price.

Step 5: Address Tax Implications: An ADU may affect capital gains tax, so it’s best to consult a tax advisor for specifics.

Step 6: Consider the Market Appeal: Include details in the listing about rental income potential, zoning, and recent renovations to the unit.

Step 7: Talk to a Real Estate Agent: Choose an expert who has enough knowledge of ADU laws, values, and market trends to effectively connect you with potential buyers.

Step 8: Market the Property: Highlight the ADU in online listings with quality photos, a clear description of its features, and potential rental income.

Step 9: Confirm Compliance with Local Regulations: Gather permits and inspection records to reassure buyers that your ADU is up to code.

FAQ:

What is an ADU home in California?

An ADU is a small, self-contained home on the same property as the main house. It’s usually tied to the main property and can’t be sold separately, though there are rare cases where an ADU is sold separately in California under specific rules.

Can I sell my ADU in California?

Usually, no. ADUs are considered part of the main property and can’t be sold on their own. However, Assembly Bill 1033 allows limited exceptions, mainly for affordable housing or specific pilot programs. Check with your local planning department to see if separate sales apply in your area.

Do I need additional parking for an ADU in Sacramento?

Under ADU rules in California, if your property is within half a mile of public transit, additional parking isn’t required. Otherwise, one parking space per ADU may be needed, depending on location and property layout.
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