How to Obtain a Permit to Legalize Unpermitted Accessory Dwelling Units
INFORMATION BULLETIN
242
May 2026
IN THIS BULLETIN:
The purpose of this bulletin is to explain the intent of California Assembly Bill (AB) 2533 and conditions by which it allows the legalization of existing accessory dwelling units (ADUs) and junior accessory dwelling units (JADU’s) originally constructed without a Building Permit.
I. ADUs & Junior Accessory Dwelling Units JADUs
ADUs are attached or detached residential dwelling units, which are secondary in nature to a primary residential dwelling unit or dwelling units on a parcel of property. Also known as “mother-in-law suites” or “granny flats”, ADUs provide complete independent living facilities for one or more people. ADUs include permanent provisions for sleeping, eating, cooking, and sanitation. A JADU is a residential dwelling unit that is no more than 500 square feet in area and contained entirely within an existing single-family residence, includes one existing bedroom and can have separate sanitation facilities from or shared sanitation facilities with the existing residence. See Information Bulletin 400 for additional information regarding ADUs and JADUs.
II. Retroactive Permitting Authorized Through State Legislation
On September 28, 2024, Assembly Bill (AB) 2533 was signed into law. This bill prohibits a local agency from denying a permit for an unpermitted accessory dwelling unit or junior accessory dwelling unit constructed before January 1, 2020, unless the local agency makes a finding that correcting the violation is necessary to address a substandard condition. The bill allows the homeowner to obtain a confidential third-party inspection by a licensed design professional or general contractor to determine the unit’s existing condition or the scope of building improvements. The full text of AB 2533 may be viewed at the following link and adopted in California Government Code Section 66311.7.
III. What is the Applicability of this Program?
This streamlined program is applicable only to ADUs and JADUs within the City of San Diego constructed without a building permit prior to January 1, 2020. The existing ADU or JADU must meet the definition in California Government Code Section 66313, and the ADU may be detached, attached, or a conversion.
Projects that do not qualify for this streamlined program and may require additional documentation, such as architectural and structural plans/calculations, soils reports, etc. include:
- Situated within a fault zone, landslide or liquefaction area.
- Created by excavating under the floor space.
- Building with materials not permissible by the Building Code.
- Located on top of a public or private easement.
- Attached to an existing apartment or commercial building.
New alterations, remodeling and/ or additions to the existing unpermitted work are required to comply with the current governing California building codes and other regulations. This bulletin shall not be utilized for unpermitted work located in areas subject to the Coastal Act regulations. Such development requires compliance with the Coastal Development requirements in San Diego Municipal Code (SDMC) Chapter 12, Article 6, Division 7.
IV. Criteria for Retroactive Building Permit Approval
In order to be considered habitable and qualifying for a retroactive building permit, the dwelling unit will need to meet various minimum standards. These standards include compliance with the items addressed in Attachment A.
To obtain the retroactive building permit, an application will be required, applicable fees must be paid, reviews will be conducted to determine compliance with the minimum requirements, and inspections will be conducted. Although the permit legitimizes the dwelling unit, certain improvements may be required to comply with basic life and safety requirements. These improvements include, but are not limited to, the installation of smoke alarms, carbon monoxide alarms, emergency escape and rescue openings and light and ventilation openings. See Attachment A for a checklist containing the list of requirements for determination if a building is considered substandard. Any item that does not comply with this list shall be corrected as a part of the building permit application.
V. Submittal Requirements
If an ADU or JADU processed per this bulletin, provide this information on the scope of work on plans and on the electronic application under the scope of work (e.g. This project proposes to use the provisions of AB 2533).
For information concerning plans, documents, and calculations required to be submitted for review, refer to Information Bulletin 140 – Residential Addition/Remodel, Section I, Submittal Requirements.
1. Evidence of Establishing the Construction Date of an Unpermitted ADU or JADU
The date of construction must be provided on the plans so that DSD can confirm applicability with this streamlined program. In addition, evidence must be provided for DSD to verify the construction date. Below are options for providing evidence of construction:
1. Contractor’s bills and/or building material receipts.
2. Utility bills or insurance documents pertaining to the unpermitted construction.
3. Code enforcement case documentation.
4. A signed and dated lease agreement.
5. Real estate documents such as loan documents, appraisal, MLS listing, etc.
6. Dated photographs.
7. Other documents acceptable to the department.
2. Building and Land Use Enforcement (BLUE) Case.
If the submittal of a permit application is in response to a notice issued by the Building and Land Use Enforcement for building code violations, then the Case Number associated with the proposed project must be indicated in the scope of work.
3. Property Information and Site Plan. The applicant will need to provide a site plan identifying the following, at a minimum:
1. Property Address and Assessor’s Parcel Number (APN).
2. North arrow and scale of drawing.
3. Property boundaries,
4. Adjacent road(s) and fire access,
5. Location of the ADU/JADU on the property, clearly marked and dimensioned,
6. Setbacks to property lines, structures, lot coverage by structures, and measurements,
7. Locations of all easements,
8. Locations of existing utility lines and connections (water, sewer, gas, electricity).
For additional information on how to prepare a site plan and vicinity map, refer to Information Bulletin 122.
4. Floor Plan. At a minimum, floor plans shall be provided with the following information:
1. Room names and dimensions of rooms to show minimum dimensions are provided.
2. Location of cooking appliances.
3. Location of toilet and sink facilities.
4. Hot water heater.
5. Heating element.
6. Smoke alarms and carbon monoxide alarms.
7. Location of exit doors and size of exit doors shown.
8. Emergency escape and rescue windows.
9. GFCI outlets, where required.
5. Completed Attachment A
VI. Additional Regulations
- Coastal Height Limitation Overlay Zone
Also referred to as “Proposition D”, buildings in this zone must comply with the supplemental height limit regulation as enacted by the voters of the City of San Diego and outlined in SDMC Chapter 13, Article 2, Division 5. For detailed information on how building height is determined for buildings and structures located in the Coastal Height Limitation Overlay Zone, refer to Technical Bulletin BLDG-5-4. - Water and Sewer Fees. The water meter will not be sized as part of this review to determine if a meter upgrade is required. No water and sewer capacity fees will apply if the project is in accordance with AB 2533. The water billing rate code may need to be updated to reflect the correct number of dwelling units. Current water billing rates can be found here: https://www.sandiego.gov/public-utilities/customer-support/water-billing-rates.
- Fire Access. The fire apparatus access/road shall comply with the requirements of California Fire Code (CFC) Section 503, with local amendments. Access shall extend to within 150 feet of all portions of the facility and all portions of the exterior walls of the first story of the buildings as measured by an approved route around the exterior of the building. If fire sprinklers are provided for the unit, the access distance can be extended to 200 feet.
- Depending on the date of original construction, the existing unpermitted building shall comply with additional regulations. If it is determined that the existing unpermitted construction, whether completed at one time or incrementally, is non-complaint with the limits of this bill, a Building Permit shall be required where the work is not exempt . For these additional requirements, refer to Information Bulletin 140 – Residential Addition and Remodel, Section II - Additional Regulations.
VII. Project Fees
The applicant will be required to pay the applicable fee(s) based on the current fee schedule. Refer to Information Bulletin 501, Fee Schedule, Construction Permits - Structures and Information Bulletin 103, Fee Schedule for Mechanical, Electrical, Plumbing/ Gas Permits for all applicable fees.
The local school district(s) may assess a school fee for new construction. Information Bulletin 146 "School Fees," provides information about school fee requirements, how the fees are calculated, and how to pay school fees to the school district prior to permit issuance. No Construction and Demolition (C&D) Debris Recycling Deposit is required for projects that qualify under AB 2533.
VIII. Permit Application Process
All new applications for permits and approvals are required to be submitted online. For the permitting of a previously unpermitted ADU, select the Building Permit application. For additional information concerning how to submit permit applications, plans, documents, and calculations online, refer to the Department’s home page at www.sandiego.gov/DSD.
IX. Inspections
Inspections will occur after permit issuance to complete the permit. The intent of these inspections is to verify that the ADU/JADU is not considered substandard as described in Attachment A. Please be advised that any additional work, or installations completed after January 1, 2020, such as home heating equipment, electrical equipment and water heaters will be inspected for compliance with the current applicable codes
For information on the inspection process and how to schedule inspections, refer to Information Bulletin 120.
X. Previous Versions of this Information Bulletin
This section contains previous versions of this Information Bulletin by the last day they were effective.
- 2026-5-20|IB-242 "How to Obtain a Permit to Legalize Unpermitted Accessory Dwelling Units"
- 2025-1-10|IB-242 "How to Obtain a Permit to Legalize Unpermitted Accessory Dwelling Units"
XI. Attachment A
Please identify on the following checklist whether the existing condition of the ADU/JADU complies or does not comply with the stated description and submit a Building Permit Application to correct any substandard conditions as defined in the Health and Safety Code.
Note: This checklist was adapted from the Health & Safety Code, Section 17920.3, to address items necessary so that a building is not considered substandard.
- Smoke Alarms
Compliant | Non-Compliant | Description |
| Operational and installed in every sleeping room | ||
| Installed outside each separate sleeping area in the immediate vicinity (hallways) | ||
| Installed on every level of the dwelling unit, including basements |
- CARBON MONOXIDE ALARMS
Compliant | Non-Compliant | Description |
Operational and installed outside each separate sleeping area in the immediate vicinity of bedrooms (hallways), on every occupiable level including basements, and in bedrooms with fireplaces. (only if required by code) | ||
If there is an attached garage with an opening into the dwelling unit, or a fuel-fired appliance or fireplace in the home, alarms shall be installed at each level of the dwelling | ||
Installed on every level of the dwelling unit, including basements |
- EMERGENCY ESCAPE AND RESCUE OPENINGS – FOR SLEEPING ROOMS
Compliant | Non-Compliant | Description |
Emergency egress windows are provided in every sleeping room | ||
The emergency egress window(s) must have a minimum clear opening width of 20 inches and a clear opening height of 24 inches and 5.7 square feet openable space or 5.0 square feet openable space on grade floor openings | ||
There are no obstructions (such as bars, grills, or security devices) that can impede escape or rescue in an emergency |
- SANITATION
Compliant | Non-Compliant | Description |
Proper water closet, lavatory, and bathtub/shower in a dwelling unit | ||
Proper kitchen sink | ||
Hot and cold running water to plumbing fixtures | ||
Adequate heating | ||
Proper operation of required ventilating equipment | ||
Minimum of 8% natural light and 4% ventilation provided based upon the floor area of the habitable room(s) | ||
Minimum room and space dimensions provided, 70 square feet or 7 feet minimum, except kitchens | ||
Required electrical lighting is provided | ||
Habitable rooms have no signs of dampness | ||
Infestation of insects, vermin, or rodents is not present | ||
Visible mold growth is not present, excluding the presence of mold that is minor and found on surfaces that can accumulate moisture as a part of their properly functioning and intended use | ||
General dilapidation or improper maintenance of the unit is not present | ||
Connection to required sewage disposal system is present | ||
Proper garbage and rubbish storage and removal facilities are present |
- STRUCTURAL HAZARDS
Compliant | Non-Compliant | Description |
Adequate and not deteriorated foundations are provided | ||
Adequate and not deteriorated flooring or floor supports are provided | ||
Flooring or floor supports are of sufficient size to carry imposed loads with safety | ||
No walls, partitions, or other vertical supports that split, lean, list, or buckle due to defective material or deterioration | ||
No walls, partitions, or other vertical supports that are of insufficient size to carry imposed loads with safety | ||
No ceilings, roofs, ceiling and roof supports, or other horizontal members which sag, split, or buckle due to defective material or deterioration | ||
No ceilings, roofs, ceiling and roof supports, or other horizontal members that are of insufficient size to carry imposed loads with safety | ||
No fireplaces or chimneys which list, bulge, or settle due to defective material or deterioration | ||
No fireplaces or chimneys which are of insufficient size or strength to carry imposed loads with safety | ||
Possible inadequate structural resistance to horizontal forces |
- NUISANCE
Compliant | Non-Compliant | Description |
All wiring, except that which conformed with all applicable laws in effect at the time of installation if it is currently in good and safe condition and working properly | ||
All plumbing, except plumbing that conformed with all applicable laws in effect at the time of installation and has been maintained in good condition, or that may not have conformed with all applicable laws in effect at the time of installation but is currently in good and safe condition and working properly, and that is free of cross connections and siphonage between fixtures | ||
All mechanical equipment, including vents, except equipment that conformed with all applicable laws in effect at the time of installation and that has been maintained in good and safe condition, or that may not have conformed with all applicable laws in effect at the time of installation but is currently in good and safe condition and working properly. | ||
There is no faulty weather protection present which may include: (1) Deteriorated, crumbling or loose plaster (2) Deteriorated or ineffective waterproofing of exterior walls, roofs, foundations or floors, including broken windows or doors (3) Defective or lack of weather protection for exterior wall coverings, including lack of paint, or weathering due to lack of paint or other approved protective covering (4) Broken, rotted, split, or buckled exterior wall coverings or roof coverings | ||
The building or portion thereof, device, apparatus, equipment, combustible waste, or vegetation is not in such a condition as to cause a fire or explosion or provide a ready fuel to augment the spread and intensity of fire or explosion arising from any cause. | ||
All materials of construction, except those that are specifically allowed or approved by this code, have been adequately maintained in good and safe condition. | ||
There is no accumulation of weeds, vegetation, junk, dead organic matter, debris, garbage, offal, rodent harborage, stagnant water, combustible materials, and similar materials or conditions that constitute fire, health, or safety hazards. | ||
The building or portion thereof is not determined to be an unsafe building due to inadequate maintenance | ||
The building or portions thereof are provided with adequate exit facilities as required by this code, except those buildings or portions thereof whose exit facilities conformed with all applicable laws at the time of their construction and have been adequately maintained and increased in relation to any increase in occupant load, alteration or addition, or any change in occupancy | ||
The building or portions thereof are provided with fire-resistive construction or fire-extinguishing systems or equipment required by this code, except those buildings or portions thereof that conformed with all applicable laws at the time of their construction and whose fire-resistive integrity and fire-extinguishing systems or equipment have been adequately maintained and improved in relation to any increase in occupant load, alteration or addition, or any change in occupancy | ||
The building or portions thereof occupied for living, sleeping, cooking, or dining purposes was designed or intended to be used for those occupancies |