All About ADUs

Thinking about adding more space to your property? Accessory Dwelling Units (ADUs) are becoming a go-to solution for homeowners who want to maximize their property’s value. Building an ADU in San Carlos is a smart investment.

With housing prices skyrocketing, ADUs are a practical way to create extra living space – perfect for aging parents, extended families, or tenants – while avoiding the high costs of traditional housing. Despite construction costs that can exceed $150,000, many ADU owners recoup their investment through long-term rental income.

Local and state governments are also making it easier than ever to build ADUs by relaxing zoning laws, offering incentives, and streamlining the approval process. Nevertheless, there’s still plenty of debate about zoning rules, parking requirements, and what to do about unpermitted units.

Some cities have size and height limits to keep ADUs from standing out too much, while others are cutting red tape to make building them easier. Parking is another big issue—since ADU residents typically own fewer cars, many cities are rethinking outdated parking requirements.

 

AdobeStock ADU

 

Free ADU Webinar in San Carlos

Before we continue, if you’re considering building an ADU or just want to learn more about the possibilities, mark your calendar for February 13 and join the “Unlocking ADUs” webinar hosted by the ADU Resource Center of San Mateo County:

 

Unlocking ADUs

SAVE EVENT TO CALENDAR 

Building an ADU in San Carlos

Whether you’re considering a detached unit in your backyard or a garage conversion, understanding local regulations is crucial. Here’s everything you need to know about building an ADU in San Carlos.

Are Accessory Dwelling Units (ADUs) Allowed by Right?

Yes, certain ADUs—referred to as Statewide Exemption ADUs—must be allowed. These units:

  • Have a maximum size of 800 square feet.
  • Must be located at least four (4) feet from side and rear property lines.
  • Can have a maximum height of 16 feet when detached or up to 25 feet when attached.
  • California law requires that at least one Statewide Exemption ADU must be permitted on any lot that allows residential uses.

For additional details, refer to the San Carlos Municipal Code: www.codepublishing.com/CA/SanCarlos/

Where Are ADUs Permitted in San Carlos?

ADUs are permitted in all zoning districts that allow residential uses, including:

  • Single-family residential (RS)
  • Multi-family residential (RM)
  • Mixed-use (MU) zoning districts

View the City’s zoning map here: www.gis.cityofsancarlos.org

What Are the Different ADU Configurations?

Homeowners have several options when it comes to ADU design, including:

  • Detached ADU (a standalone unit separate from the main home)
  • Attached ADU (connected to the main home)
  • Interior (Basement) ADU
  • Attached (Above Garage) ADU
  • Interior (Converted Garage) ADU
  • Interior (Upper Floor) ADU

 

ADU Types Diagram

Different Types of ADUs

Where Can I Find ADU Development Regulations?

For more information on building requirements, visit: www.cityofsancarlos.org/ADU

Contact the San Carlos Planning Department:

  • Email: planning@cityofsancarlos.org
  • Phone: (650) 802-4263
  • Planning Counter Hours: Monday – Thursday, 9:00 AM to 12:00 PM
  • Address: 600 Elm Street, San Carlos, CA

Where Can I Find Approximate Costs?

The cost of an ADU varies depending on size, materials, and any additional requirements such as tree protection. To estimate your potential ADU costs, use the construction cost calculator: www.smcadu.org/resources/calculator/

 

San Diego ADUs Ruland Design Group

San Diego ADUs by Ruland Design Group

How Do I Submit a Building Permit for an ADU?

ADU permit applications can be submitted directly to the San Carlos Building Department.

Building Counter Hours:

  • Monday – Thursday, 9:00 AM to 12:00 PM
  • Address: 600 Elm Street, San Carlos, CA

Contact the Building Department:

How Is San Carlos Supporting ADU Development?

The City of San Carlos actively encourages ADU development by: ✔ Supporting well-designed ADUs that blend into existing neighborhoods. ✔ Promoting the legalization of unpermitted ADUs to ensure safety and habitability. ✔ Providing public education materials on planning, permitting, and funding opportunities.

Additional Resources

San Carlos is a member of the ADU Resource Center, which assists San Mateo County residents in navigating the ADU development process. Visit: www.smcadu.org

Photos are courtesy of ABCs of ADUs from the American Planning Association, and Adobe Stock Images.


For More News

For more of what’s happening in and around San Carlos, please visit San Carlos Life Blog

About San Carlos Life

Mark Martinho and Vivienne Kelvin are the hosts of San Carlos Life and have been residents of San Carlos for years. While running San Carlos Life together with an awesome team, Mark and Viv are also in the business of real estate. They are co-owners of Vabrato Real Estate, a luxury real estate brokerage serving the City of Good Living, and the whole of San Mateo and Santa Clara counties.

With over 30 years of combined experience in the business and 95% of their clients coming in from referrals, Mark and Viv take great pride and joy in exceeding your expectations.

Contact Mark and Viv of Vabrato Real Estate

 

Don't miss out!
Subscribe To San Carlos Life

Add your email here to subscribe to all things San Carlos

Invalid email address
Give it a try. You can unsubscribe at any time.