If you’ve been watching San Diego’s evolving stance on Accessory Dwelling Units (ADUs), you’ve probably noticed the city's generous bonus program take center stage—and then promptly step back. In June 2025, the City Council voted to scale back that program in a move that signals a sharper focus on neighborhood character, infrastructure strain, and fire safety.
This blog explains what those changes mean for property owners and developers—and how many units you can actually build now.
The Old Model: What Made San Diego a “Bonus ADU” Hotspot
Until recently, San Diego was one of the most ADU-friendly jurisdictions in the state. The bonus program allowed homeowners to go far beyond the standard state law, permitting up to 6 units per lot in single-family zones—if certain affordability conditions were met.
That generosity triggered a wave of multi-unit backyard developments. In some cases, homeowners squeezed a surprising number of small rentals onto suburban lots. This led to an uptick in affordable housing—but also community pushback.
The June 2025 Vote: A Quick Recap
On June 16, 2025, the San Diego City Council voted 5–4 in favor of capping the number of ADUs that can be built under the Affordable Bonus ADU program. Here’s what that looks like now:
Lots 8,000 square feet or smaller: Up to 4 total ADUs
Lots between 8,001–10,000 square feet: Up to 5 total ADUs
Lots over 10,000 square feet: Up to 6 total ADUs
This replaces the previous framework, which had no cap—at least in practical terms. The new limits apply citywide and took effect shortly after the vote.
How This Affects You: One Lot, Multiple Paths
If you’re a homeowner or investor, the change isn’t just academic. It directly limits your development scope.
Let’s say you own a 7,500 sq ft lot in a single-family zone. Under the prior rules, you could have applied for as many bonus ADUs as your site plan, infrastructure, and affordability requirements allowed—sometimes 6 units or more. Now, your cap is four, total.
This means careful site planning just became critical. If you were hoping to go vertical or stack modulars to hit 6 units on a small lot, you may need to pivot.
A Closer Look: The Math Behind the Cap
The new cap is tied directly to lot size, not zoning type. That’s a key distinction. Prior versions of the program leaned heavily on zoning and whether the parcel was within a Transit Priority Area (TPA). While TPA eligibility still plays a role (especially for parking exemptions), the cap itself doesn’t flex based on transit access.
So, whether you're in North Park or Clairemont, the numbers stay the same. What changes is how you use them.
Let’s run a few hypotheticals:
- Scenario A: 6,000 sq ft lot in a TPA→ Max units: 4 (includes any required affordability bonus units)→ You likely won’t need replacement parking.
- Scenario B: 9,000 sq ft lot not in a TPA→ Max units: 5→ Parking may be required for new ADUs.
- Scenario C: 11,000 sq ft lot in a coastal zone→ Max units: 6→ Additional review steps may apply (e.g., Coastal Development Permit).
These examples assume you meet other eligibility requirements like affordability, fire safety, setbacks, and access.
What Qualifies as an “ADU” in the Cap?
San Diego offers a library of pre-approved floor plans to cut red tape. You still need:
Site plan
Structural foundation info
Utility layout
Why the Rollback? Pressure Came from All Sides
This wasn’t a change that came out of nowhere. The council has faced growing pressure from neighborhood groups, especially in RS-1 zones and high fire-risk areas. Concerns centered on:
Strain on aging sewer and water systems
Increased vehicle traffic and parking overflow
Evacuation challenges in dead-end neighborhoods
Visual and noise impacts in low-density areas
One incident in Pacific Beach—where a developer squeezed 16 bedrooms onto a single lot—fueled the narrative that the program was being exploited.
What the State Thinks: Sacramento Isn’t Happy
Not everyone agrees with the rollback. On June 13, the California Department of Housing and Community Development (HCD) issued a letter to San Diego warning that the changes may violate state housing goals.
The main argument: capping bonus ADUs may reduce the production of deed-restricted affordable units, which cities are obligated to prioritize.
San Diego could risk losing its Prohousing Designation if the state determines that the rollback creates “constraints on housing development.”
It’s too early to tell how this will play out, but legal challenges—or legislative responses—are not off the table.
Still Building? You’ve Got Options
If you're in the middle of designing or permitting a project based on the old rules, don’t panic. There’s often a transitional grace period for submittals made before the effective date. You’ll need to check with San Diego’s Development Services Department (DSD) to see if you qualify.
Also, if you’re already entitled under a previous approval, you can generally proceed as planned. Just make sure your entitlements are current and in writing.
Does This Kill the ADU Boom?
Not exactly. ADUs are still legal in every residential zone in California. What San Diego did was apply a brake—not a full stop. You can still:
Build a detached ADU and JADU by right
Build additional units if you meet affordability guidelines
Avoid parking requirements in TPAs
Use prefab/modular builders to speed up timelines
But now, you have to play within a tighter framework. That means more planning and fewer assumptions.
Final Takeaway: Build Smarter, Not Bigger
San Diego’s bonus ADU cap signals a new chapter: one where balance wins out over raw unit counts. The opportunity’s still there, but now it comes with a set of clearly drawn lines.
If you’re looking to build, remodel, or invest, don’t just chase the maximum unit count. Instead, look at:
Lot efficiency
Code compliance
Affordability program requirements
Neighborhood compatibility
And yes, work with a qualified designer or land-use expert who knows the local permitting maze.
In this new environment, smart beats ambitious.
