San Diego’s 2025 ADU Laws: Build, Legalize & Maximize Value

Introduction

San Diego has long been at the forefront of ADU (Accessory Dwelling Unit) development in California. With housing affordability still a critical issue, the city’s 2025 updates to its ADU regulations aim to strike a balance between neighborhood preservation and housing expansion. Whether you're looking to build a new ADU, legalize an existing one, or understand your permit options, these updates directly impact your plans.

2025 ADU Regulation Changes – What's New?

San Diego's City Council has scaled back its previous “Bonus ADU” program, which allowed multiple ADUs on a single-family lot if at least one unit was affordable. While the city still complies with California's base ADU laws, new local policies introduce restrictions in response to community concerns about overcrowding and infrastructure strain.

Overview of San Diego’s 2025 ADU Law Changes:

Aspect	2024 Rules	2025 Changes
Bonus ADU Program	Multiple ADUs allowed with affordability commitment	Phased out in single-family zones
Permit Timeline	60–120 days (target)	Still targeted, but real approval takes ~200+ days
Setbacks and Parking	Reduced setbacks and parking exemptions	Stricter setbacks and parking now required in many zones
Unpermitted ADUs	Legalization available, but with penalties	Now allowed without penalties if safety standards are met
Coastal Zone Rules	Subject to Coastal Commission approval	No major changes, still requires additional review

How to Get an ADU Permit in San Diego

Securing an ADU permit in San Diego involves a structured, step-by-step process. Compliance with state housing laws and San Diego’s local ordinances is crucial to avoid costly delays or rejections.

Step-by-Step Guide:

Determine Zoning Eligibility
Use the San Diego Development Services website to check if your lot qualifies. Zoning, lot size, and overlays (like coastal zones or fire hazard areas) will affect eligibility.
Select Your ADU Type
Decide whether to build a detached ADU, garage conversion, attached unit, or junior ADU (JADU).
Prepare Plans & Documentation
Hire an architect or contractor to draft plans including:
- Site plan
- Floor plan
- Title 24 energy report
- Structural and MEP (Mechanical, Electrical, Plumbing) documents
Submit Application
Apply online through San Diego’s DSD portal. Include all required forms, fees, and plans.
Wait for Review (Ministerial Process)
If your plans meet all local and state ADU guidelines, they’ll be approved without discretionary hearings.
Construction & Final Inspection
Begin construction only after receiving your permit. Final inspection is required for occupancy approval.

Legalizing Unpermitted ADUs in 2025

Thanks to AB 2533, a major breakthrough in 2025, property owners can now legalize previously unpermitted ADUs without penalty, provided the structure meets health and safety requirements.

Requirements for Legalization:

The ADU must have been built before January 1, 2020
It must meet basic safety standards (electrical, fire, sanitation)
An inspection must be passed before final approval

This move is especially helpful for homeowners with existing units looking to rent them legally or refinance their property.

Top ADU Permit Companies in San Diego

Getting an ADU permit isn’t always easy. These local companies are recognized for their efficiency, knowledge of San Diego's ADU regulations, and successful project delivery.

Company Name	Services Offered	Why Choose Them
SnapADU	Design, permitting, and construction	Streamlined ADU expertise, fast approvals, and transparent pricing
Better Place Design & Build	Turnkey ADU services across San Diego	Excellent local reviews, experienced with JADUs and conversions
H&M Building Services LLC	Garage conversions, new ADUs, custom designs	Fast approvals using pre-approved plans
Coastal ADU Solutions	Permit consulting and project management	Ideal for owners in coastal or fire-zone overlays

How to Maximize Value from Your ADU in 2025

Building or legalizing an ADU is one of the best ways to increase your property’s market value in San Diego. Here's how to do it right:

Value-Boosting Tips:

✅ Legalize First: A legalized ADU can increase home value by 20–30%.
✅ Upgrade Features: Energy-efficient appliances, high-end finishes, and modern layouts boost both rent and appraisal.
✅ Build Detached if Possible: Detached ADUs are more desirable for renters and buyers.
✅ Separate Utilities: Install separate meters for water and electricity if renting long-term.
✅ Use Professional Services: Top ADU permit companies streamline your experience and reduce legal risk.

FAQ

Can I build more than one ADU on my property in 2025?

Not anymore. The bonus ADU program has been rolled back. Most single-family lots are now allowed one ADU and one JADU.

How long does it take to get an ADU permit in San Diego?

While the city targets a 60–120 day timeline, actual average approval is closer to 200–220 days, depending on the plan quality and zone.

Do I need to legalize my existing unpermitted ADU?

Yes, especially if you plan to rent it legally, refinance, or sell your property. AB 2533 allows legalization without penalties.

Are ADUs still allowed in coastal areas?

Yes, but you may need an additional coastal permit. Working with companies familiar with coastal overlays is highly recommended.

What is the best way to speed up ADU approval?

Use pre-approved plans and work with top-rated permit service providers like SnapADU or Better Place Design & Build.