Can I Build an ADU on my Lot in San Diego?

One of the most common questions homeowners in San Diego ask is, "Can I build an Accessory Dwelling Unit (ADU) on my lot?"

The short answer is yes—but there are some specifics you need to know depending on your lot’s zoning and location. Let’s break it down to make it simple.

What Qualifies a Lot for an ADU?

Residential Zoning: RS and RM

If your lot is zoned for residential use, then it qualifies for an ADU. This includes:

• RS Zones (Residential Single-Family): These lots qualify for one ADU and one Junior Accessory Dwelling Unit (JADU) in addition to the primary dwelling unit.
• RM Zones (Residential Multi-Family): These lots allow for two ADUs but do not allow for a JADU. However, there is potential for additional ADUs if the lot falls under specific overlays like the Transit Priority Overlay Zone.

Commercial Zoned Lots

Certain commercial zones may also qualify for an ADU if the lot permits mixed-use structures (residential and commercial). However, the regulations surrounding commercial zoning for ADUs are less clear compared to RS and RM zones.

How to Check Your Lot's Zoning

Not sure what zone your lot is in? Use these tools to find out:

• Google San Diego Zoning Validation to access zoning maps.
• Use the San Diego Zoning Portal (ZAPP) to confirm your lot’s zoning designation.

Key Regulations for ADU Development

RS Zones: Residential Single-Family

If your lot is in an RS zone, you can build:

• 1 ADU (Accessory Dwelling Unit)
• 1 JADU (Junior Accessory Dwelling Unit)

This is in addition to the primary residence already on the lot.

RM Zones: Residential Multi-Family

If your lot is zoned RM, the rules are slightly different:

• You cannot build a JADU.
• You can build up to 2 ADUs by default.
• If your lot is located in a Transit Priority Overlay Zone, you may qualify for more than 2 ADUs, depending on specific conditions. This can provide additional development opportunities within San Diego’s zoning framework.

Summary of ADU Eligibility

Here’s a quick recap of what’s possible:

• RS Zoned Lots: Eligible for 1 ADU + 1 JADU
• RM Zoned Lots: Eligible for 2 ADUs, with the potential for more in Transit Priority Overlay Zones
• Commercial Zoned Lots: May qualify for ADUs in mixed-use projects (case-by-case basis)

Ready to Build an ADU?

If you’re ready to explore building an ADU on your lot, we’re here to help. Fill out our interactive project survey in order to schedule a consultation and discuss your lot’s unique potential, navigate zoning regulations, and bring your vision to life.