What you can build

La Mesa ADU Regulations & Zoning

ADU regulations are complex, but when you've done this for 100+ projects, you know the details inside and out. We publish our insights because we want people to get accurate information, not just regurgitated bullet points.
Size and Separation
Maximum size
1200sqft
Side/rear setbacks
4 feet
Two story
Building separation
6 Feet
Permitting timeline
Standard Timeline
3-5 months
Permit Costs
$5-18/sqft
Additional Requirements
Soils Report
Building Survey
Stormwater Mitigation

ADU Site Overview

What You Can Build—and What to Expect

When do County of Bay Area ADU regulations apply?

‍

Planning an Accessory Dwelling Unit (ADU) starts with knowing what’s possible on your property. Here’s a quick snapshot of the key build guidelines and permitting details to help you move forward with clarity.

‍

You can build an ADU up to 1,200 square feet, with just 4-foot setbacks from the side and rear property lines. Two-story ADUs are allowed, offering flexibility for families, rentals, or multi-generational living. Your ADU must maintain a minimum 6-foot separation from other structures on the lot.

‍

Permitting typically takes 3 to 5 months, depending on your city and project scope. Permit costs range from $5 to $18 per square foot, with coastal zone timelines still to be determined.

‍

The good news? Most projects do not require a soils report, building survey, coastal permit, or stormwater mitigation, making the process smoother and more accessible.

‍

Find MY ADU Plan

What Are the Rules for ADUs in 

La Mesa

?

We’re glad you asked! Check out our summary below, where you can find how many ADUs you can build, plus limitations for size, setbacks and other additional requirements. We’ve included our own experience with how the laws are interpreted based on designing, permitting & building many ADUs in the County.

Number of ADUs Allowed

How many ADUs can you build in 
La Mesa
?
Right-facing chevron iconGraphic illustration

Lorem ipsum dolor sit amet, consectetur adipiscing elit. Suspendisse varius enim in eros elementum tristique. Duis cursus, mi quis viverra ornare, eros dolor interdum nulla, ut commodo diam libero vitae erat. Aenean faucibus nibh et justo cursus id rutrum lorem imperdiet. Nunc ut sem vitae risus tristique posuere.

How many ADUs are allowed on multifamily properties?
Right-facing chevron iconGraphic illustration

Lorem ipsum dolor sit amet, consectetur adipiscing elit. Suspendisse varius enim in eros elementum tristique. Duis cursus, mi quis viverra ornare, eros dolor interdum nulla, ut commodo diam libero vitae erat. Aenean faucibus nibh et justo cursus id rutrum lorem imperdiet. Nunc ut sem vitae risus tristique posuere.

Can you build a JADU in 
La Mesa
?
Right-facing chevron iconGraphic illustration

Lorem ipsum dolor sit amet, consectetur adipiscing elit. Suspendisse varius enim in eros elementum tristique. Duis cursus, mi quis viverra ornare, eros dolor interdum nulla, ut commodo diam libero vitae erat. Aenean faucibus nibh et justo cursus id rutrum lorem imperdiet. Nunc ut sem vitae risus tristique posuere.

Are guest quarters allowed in addition to ADUs?
Right-facing chevron iconGraphic illustration

Lorem ipsum dolor sit amet, consectetur adipiscing elit. Suspendisse varius enim in eros elementum tristique. Duis cursus, mi quis viverra ornare, eros dolor interdum nulla, ut commodo diam libero vitae erat. Aenean faucibus nibh et justo cursus id rutrum lorem imperdiet. Nunc ut sem vitae risus tristique posuere.

ADU Size Limits

What is the maximum size for a detached ADU in 
La Mesa
?
Right-facing chevron iconGraphic illustration

Lorem ipsum dolor sit amet, consectetur adipiscing elit. Suspendisse varius enim in eros elementum tristique. Duis cursus, mi quis viverra ornare, eros dolor interdum nulla, ut commodo diam libero vitae erat. Aenean faucibus nibh et justo cursus id rutrum lorem imperdiet. Nunc ut sem vitae risus tristique posuere.

What is the maximum size for an attached ADU in 
La Mesa
?
Right-facing chevron iconGraphic illustration

Lorem ipsum dolor sit amet, consectetur adipiscing elit. Suspendisse varius enim in eros elementum tristique. Duis cursus, mi quis viverra ornare, eros dolor interdum nulla, ut commodo diam libero vitae erat. Aenean faucibus nibh et justo cursus id rutrum lorem imperdiet. Nunc ut sem vitae risus tristique posuere.

Are there lot coverage exemptions for ADUs?
Right-facing chevron iconGraphic illustration

Lorem ipsum dolor sit amet, consectetur adipiscing elit. Suspendisse varius enim in eros elementum tristique. Duis cursus, mi quis viverra ornare, eros dolor interdum nulla, ut commodo diam libero vitae erat. Aenean faucibus nibh et justo cursus id rutrum lorem imperdiet. Nunc ut sem vitae risus tristique posuere.

About MolaADU

At MolaADU, we specialize in helping homeowners unlock the full potential of their properties through smart, well-designed Accessory Dwelling Units (ADUs). With over 100 successful projects across the County, we’ve built deep expertise in interpreting local regulations, navigating permitting challenges, and designing ADUs that truly work for families, renters, and communities.

This page offers a clear summary of what’s allowed—how many ADUs you can build, size limits, setbacks, and other key requirements. But we go beyond the basics. Our insights are grounded in real-world experience, not just recycled bullet points.

Whether you're planning a rental unit, a guest house, or a space for multigenerational living, we’re here to help you move forward with clarity and confidence.
Learn More

Height & Setbacks

What is the maximum height for an ADU in 
La Mesa
?
Right-facing chevron iconGraphic illustration

Lorem ipsum dolor sit amet, consectetur adipiscing elit. Suspendisse varius enim in eros elementum tristique. Duis cursus, mi quis viverra ornare, eros dolor interdum nulla, ut commodo diam libero vitae erat. Aenean faucibus nibh et justo cursus id rutrum lorem imperdiet. Nunc ut sem vitae risus tristique posuere.

Can you build a two-story ADU in 
La Mesa
?
Right-facing chevron iconGraphic illustration

Lorem ipsum dolor sit amet, consectetur adipiscing elit. Suspendisse varius enim in eros elementum tristique. Duis cursus, mi quis viverra ornare, eros dolor interdum nulla, ut commodo diam libero vitae erat. Aenean faucibus nibh et justo cursus id rutrum lorem imperdiet. Nunc ut sem vitae risus tristique posuere.

What are the side and rear setback requirements for an ADU in 
La Mesa
?
Right-facing chevron iconGraphic illustration

Lorem ipsum dolor sit amet, consectetur adipiscing elit. Suspendisse varius enim in eros elementum tristique. Duis cursus, mi quis viverra ornare, eros dolor interdum nulla, ut commodo diam libero vitae erat. Aenean faucibus nibh et justo cursus id rutrum lorem imperdiet. Nunc ut sem vitae risus tristique posuere.

What is the front yard setback requirement?
Right-facing chevron iconGraphic illustration

Lorem ipsum dolor sit amet, consectetur adipiscing elit. Suspendisse varius enim in eros elementum tristique. Duis cursus, mi quis viverra ornare, eros dolor interdum nulla, ut commodo diam libero vitae erat. Aenean faucibus nibh et justo cursus id rutrum lorem imperdiet. Nunc ut sem vitae risus tristique posuere.

What is the minimum building separation from existing structures?
Right-facing chevron iconGraphic illustration

Lorem ipsum dolor sit amet, consectetur adipiscing elit. Suspendisse varius enim in eros elementum tristique. Duis cursus, mi quis viverra ornare, eros dolor interdum nulla, ut commodo diam libero vitae erat. Aenean faucibus nibh et justo cursus id rutrum lorem imperdiet. Nunc ut sem vitae risus tristique posuere.

Permitting & Timeline

How long does it take to get an ADU permit in 
La Mesa
?
Right-facing chevron iconGraphic illustration

Lorem ipsum dolor sit amet, consectetur adipiscing elit. Suspendisse varius enim in eros elementum tristique. Duis cursus, mi quis viverra ornare, eros dolor interdum nulla, ut commodo diam libero vitae erat. Aenean faucibus nibh et justo cursus id rutrum lorem imperdiet. Nunc ut sem vitae risus tristique posuere.

What are the permit costs in 
La Mesa
?
Right-facing chevron iconGraphic illustration

Lorem ipsum dolor sit amet, consectetur adipiscing elit. Suspendisse varius enim in eros elementum tristique. Duis cursus, mi quis viverra ornare, eros dolor interdum nulla, ut commodo diam libero vitae erat. Aenean faucibus nibh et justo cursus id rutrum lorem imperdiet. Nunc ut sem vitae risus tristique posuere.

Is a soils report or building survey required?
Right-facing chevron iconGraphic illustration

Lorem ipsum dolor sit amet, consectetur adipiscing elit. Suspendisse varius enim in eros elementum tristique. Duis cursus, mi quis viverra ornare, eros dolor interdum nulla, ut commodo diam libero vitae erat. Aenean faucibus nibh et justo cursus id rutrum lorem imperdiet. Nunc ut sem vitae risus tristique posuere.

Are there stormwater mitigation requirements?
Right-facing chevron iconGraphic illustration

Lorem ipsum dolor sit amet, consectetur adipiscing elit. Suspendisse varius enim in eros elementum tristique. Duis cursus, mi quis viverra ornare, eros dolor interdum nulla, ut commodo diam libero vitae erat. Aenean faucibus nibh et justo cursus id rutrum lorem imperdiet. Nunc ut sem vitae risus tristique posuere.

Parking Requirements

What are the parking requirements for an ADU in 
La Mesa
?
Right-facing chevron iconGraphic illustration

Lorem ipsum dolor sit amet, consectetur adipiscing elit. Suspendisse varius enim in eros elementum tristique. Duis cursus, mi quis viverra ornare, eros dolor interdum nulla, ut commodo diam libero vitae erat. Aenean faucibus nibh et justo cursus id rutrum lorem imperdiet. Nunc ut sem vitae risus tristique posuere.

Do I need to replace parking if I convert my garage?
Right-facing chevron iconGraphic illustration

Lorem ipsum dolor sit amet, consectetur adipiscing elit. Suspendisse varius enim in eros elementum tristique. Duis cursus, mi quis viverra ornare, eros dolor interdum nulla, ut commodo diam libero vitae erat. Aenean faucibus nibh et justo cursus id rutrum lorem imperdiet. Nunc ut sem vitae risus tristique posuere.

Where can required parking spaces be located?
Right-facing chevron iconGraphic illustration

Lorem ipsum dolor sit amet, consectetur adipiscing elit. Suspendisse varius enim in eros elementum tristique. Duis cursus, mi quis viverra ornare, eros dolor interdum nulla, ut commodo diam libero vitae erat. Aenean faucibus nibh et justo cursus id rutrum lorem imperdiet. Nunc ut sem vitae risus tristique posuere.

ADU Costs & Rental Income

How much does it cost to build an ADU in 
La Mesa
?
Right-facing chevron iconGraphic illustration

Lorem ipsum dolor sit amet, consectetur adipiscing elit. Suspendisse varius enim in eros elementum tristique. Duis cursus, mi quis viverra ornare, eros dolor interdum nulla, ut commodo diam libero vitae erat. Aenean faucibus nibh et justo cursus id rutrum lorem imperdiet. Nunc ut sem vitae risus tristique posuere.

How much will an ADU rent for in 
La Mesa
?
Right-facing chevron iconGraphic illustration

Lorem ipsum dolor sit amet, consectetur adipiscing elit. Suspendisse varius enim in eros elementum tristique. Duis cursus, mi quis viverra ornare, eros dolor interdum nulla, ut commodo diam libero vitae erat. Aenean faucibus nibh et justo cursus id rutrum lorem imperdiet. Nunc ut sem vitae risus tristique posuere.

What factors affect ADU construction costs?
Right-facing chevron iconGraphic illustration

Lorem ipsum dolor sit amet, consectetur adipiscing elit. Suspendisse varius enim in eros elementum tristique. Duis cursus, mi quis viverra ornare, eros dolor interdum nulla, ut commodo diam libero vitae erat. Aenean faucibus nibh et justo cursus id rutrum lorem imperdiet. Nunc ut sem vitae risus tristique posuere.

Rent Rates in 
La Mesa
Neighborhood
1BR
2BR
3BR

Contact us

Get in touch with our team to start your ADU project. Whether you have questions about what's possible on your property or you're ready to begin the design process, we're here to help. Fill out the form and tell us about your goals.

We'll review your property, put together a cost estimate, and walk you through what comes next. Consultations are always free with no obligation.
408-504-7178
info@molaconstruction.com
1294 Caldwell Ct, Sunnyvale, CA 94087
Thank you! Your submission has been received!
Oops! Something went wrong while submitting the form.
MolaADU is the leading Bay Area ADU design and build company. We specialize in designing and building high-quality, custom ADUs that meet your unique needs and budget.
Quick Links
About UsGalleryHow it worksADU / Floor planProjectsADU InformationContact UsADU BasicsADU CostsADU STR Info
Office
1294 Caldwell Ct, Sunnyvale, CA 94087
© 2025 All Rights Reserved

Website designed & built by SavClicks