ADU Builders San Marcos

The San Marcos ADU Guide

San Marcos, CA, USA

You’ve found the ultimate resource for building an accessory dwelling unit in San Marcos, California. Whether you’re a homeowner looking to maximize flexibility for family or an investor planning to add units, our comprehensive guide is here to assist you every step of the way. Read on for more on what you can build in San Marcos, rent rates, and to see completed & active projects we are building. You can also access detailed ADU cost & floor plan information, plus check out homeowner stories.


What you can build

Maximum size: 1,000 square feet

Side/rear setbacks: 4 feet

Two story: Yes, above garage

Permitting timeline

Standard: 4-6 months

Coastal: N/A

Our ADU experience in San Marcos

We’ve been honored to be selected to design the City of San Marcos pre-approved ADU plans, which will be released in 2024. SnapADU has permitted or is in the process of permitting numerous projects within the city, and we know the city’s regulations and processes very well.

One unusual requirement in San Marcos is that ADUs generally cannot be in the front yard (though SB-897 passed Aug 2022 will limit city’s ability to enforce this). They also require a soils report for ADUs >500 sqft. San Marcos allows for digital submissions. Turnaround times at the city are moderate.

Additionally, we have seen San Marcos projects require interaction with the Community Facilities Districts (CFD), which are commonly referred to as Mello-Roos Districts, to finance local public facilities and services. This can add months to the processing time.

San Marcos ADU Regulations & Permitting Requirements

Want to learn more about what kind of ADU you can build in San Marcos? Check out our in-depth resource guide San Marcos Regulations & Permitting Requirements outlining the ADU building code requirements. We also include what we have learned about how the city will interpret code based on actually designing & building in the city. You can also set up a consult if you want our advice on what you can build.
San Marcos ADU Regulations

How much will an ADU rent for in San Marcos?

Below are median rental prices by zip code and bedroom count. Be sure to run comps for your specific area or check with a realtor.

92069San MarcosSan Marcos217527503575
92078San MarcosSan Marcos242534253725

Source: Rentometer March 2024

Zip Codes: 92069, 92078

Neighborhoods: Richmar, College Area, University Commons, Twin Oaks Valley, San Elijo Hills, Village O

San Marcos ADU Builders

Full Accountability. ADU Expertise. Proven Results.

Our own team is responsible for delivering on our promises, from the first time you contact us to the time we hand you the keys to your new ADU home.

As experienced ADU builders, we will anticipate the pitfalls that less seasoned or less integrated teams will miss. And the volume of ADU jobs we handle means we have gained an incredible amount of expertise that we are excited to bring to your project.

We’re 100% focused on being the best ADU builders in San Marcos.

  • House younger family members

    Provide a space of independence yet proximity for younger family members.

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  • ADU Builders San Marcos
  • We decided to build an ADU because our family's property is a big lot. That's hard to find these days, especially with the cost of housing. Plus we are closer to my mom.

    Marina & Will
    ADU Residents, San Marcos
    See the full story & ADU