What you can build
Imperial Beach 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. Our summary was last updated in November 2025.
Key Facts SnapShot
Size and Separation
Maximum size 1,200 square feet
Side/rear setbacks 4 feet
Two story Yes, in some situations
Building separation 10 feet
Additional Requirements
Soils Report No
Building Verification Survey No
Coastal permit (in some areas) Yes
Stormwater Mitigation No
Permitting timeline
Standard Timeline: 4-6 months
Coastal Timeline: TBD
Permit Costs: $8-10/sqft
Our ADU experience in Imperial Beach
SnapADU has a wealth of experience navigating the specific regulations and complexities of building ADUs throughout Coastal San Diego County. The city of Imperial Beach permits ADUs up to 1,200 sqft, presenting ample space for creative, efficient design.
However, with a large portion of Imperial Beach located within the coastal zone, there are extra layers of permitting to consider. These coastal regulations can pose unique challenges, but our team’s extensive expertise in this area ensures a smoother, more predictable process.
At SnapADU, we’re committed to making the most of your property, delivering top-quality ADUs while ensuring full regulatory compliance and maximized efficiency in design and construction. We’re familiar with the specifics, we’ve navigated the challenges, and we’re ready to bring your vision to life in Imperial Beach.
Number of ADUs Allowed
How many ADUs can you build in Imperial Beach?
On single-family residential lots in Imperial Beach, you may build one ADU (either attached or detached) and one Junior ADU (JADUs have an owner occupancy requirement and must be converted from existing space within the primary residence).
2025 UPDATE: The 2025 HCD handbook clarified that you may have one single-family converted ADU, one JADU (a conversion of existing space up to 500 sf) and one detached ADU. Prior to this clarification, there was confusion if having a converted ADU plus a JADU would prevent a homeowner from building a detached ADU. Only one detached ADU is still allowed.
How many ADUs does Imperial Beach allow for multifamily properties?
If you have more than one existing dwelling unit on your property, use these regulations:
Lots with existing or proposed multiple-family dwellings (e.g. two or more attached units on one lot, like a duplex):
1. Up to two detached Accessory Dwelling Units, and
2. The conversion of portions of multiple-family structures that are not used as living space to create at least one internal Accessory Dwelling Unit, or up to twenty-five percent of the number of existing dwelling units as internal Accessory Dwelling units
Lots with more than one existing or proposed single-family dwelling (e.g. two houses on one lot): One internal or detached Accessory Dwelling Unit per lot.
Effective Jan 2025 (SB1211): Multifamily property owners are permitted to build as many ADUs as there are existing units, with a maximum of eight detached ADUs. This change is due to California state law and will pre-empt existing local laws that are not brought into conformance.
ADU Size & Building Constraints
What size ADU can you build in Imperial Beach?
Imperial Beach allows for a detached ADU up to 1200 sqft. ADUs up to 800 square feet are exempt from lot coverage requirements. (Meaning: You can build an ADU of this size even if you’re maxed out on lot coverages).
What is the height requirement for an ADU in Imperial Beach? Can you build a 2-story ADU in Imperial Beach?
Imperial Beach follows state guidelines, which says that the height of a detached ADU can be up to 16′. Detached ADUs within half a mile of major transit stops or high-quality transit corridors can be 18′ tall. ADUs may be up to 18′ on a lot with an existing or proposed multifamily, multistory dwelling.
What are the requirements of the exterior of the ADU?
There are no specific rules regarding the exterior of the ADU per state regulations.
Setbacks
What is the setback requirement for an ADU in Imperial Beach?
A new attached or detached accessory dwelling unit is allowed a setback of no less than four feet from the side and rear lot lines. In addition, an encroachment into the front yard setback is also allowed only if it is necessary to construct a minimum 800-square-foot unit.
What is the minimum distance the ADU must be from existing structures?
For most zones in Imperial Beach, no building shall be located less than ten feet from any other building on the same lot. (Ord. 94-884; Ord. 601 § 1, 1983).
Additional Requirements
Does Imperial Beach require in-person submission of plans for an ADU?
No, Imperial Beach allows digital submission of applications for an ADU.
Does Imperial Beach require a soils report for an ADU?
Imperial Beach does not explicitly state if a soils report is required.
Does Imperial Beach require coastal development permits?
Yes, accessory dwelling units developed within the coastal zone of Imperial Beach are subject to the approval of an Administrative Coastal Development Permit by the community development department. No public hearing shall be required for permit approval. The additional cost for a coastal permit is $600.
Note that some areas of Imperial Beach that are in the coastal zone are regulated by the California Coastal Commission, which means the permit is applied for differently and may have higher fees.
Read more about ADUs in the coastal zone. Also see the City of Imperial Beach’s overview of What Triggers a Coastal Permit for ADUs.
Multifamily
How many ADUs does Imperial Beach allow for multifamily properties?
Multifamily property owners are permitted to build as many ADUs as there are existing units, with a maximum of eight detached ADUs. This change is due to California state law and will pre-empt existing local laws that are not brought into conformance.
Additionally, a minimum of one accessory dwelling unit, or up to 25 percent of the existing multifamily units, is permitted within an existing multifamily dwelling, as a result of the conversion of non-habitable space including, but not limited to, storage rooms, boiler rooms, passageways, attics, basements, or garages.
Note that multifamily building would be a duplex, triplex, etc. Two detached single-family homes on a lot would not count as multi-family dwellings, and only one ADU and one JADU could be built in that context (confirmed by email June 2024 by the Imperial Beach planning department).
Can you stack detached ADUs on top of each other?
Yes, you can stack detached ADUs on top of each other on multifamily properties (confirmed by an associate planner in Imperial Beach via email in June 2024).
Can you attach two ADUs to each other in Imperial Beach?
Yes, as long as they comply with the underlying zoning, you may attach two ADUs.
Can you convert existing space to an ADU?
Non‐livable space within existing multi‐family structures may be converted into an ADU. Examples of areas that can be converted include storage rooms and garage spaces. The maximum number of ADU allowed in a multi‐family structure is equal to 25% of the number of existing multi‐family units in the structure. A minimum of one conversion ADU is allowed.
Parking
What is the parking requirement for an ADU in Imperial Beach?
A parking space is not required for an ADU in any of the following instances:
- Within a one-half mile walking distance from public transit, which includes bus stops.
- Within an established historic district.
- Converted from the existing space of a primary residence or accessory structure, or are attached to an existing or proposed primary residence.
Effective Jan 2025 (SB1211): When a garage, carport, covered parking structure, or uncovered parking space is demolished or converted for construction of an ADU, replacement parking will not be required.
Where can a parking space be located?
If a parking space is required, it may be located within the setbacks and in an existing driveway as tandem parking. Parking spaces don’t need to be replaced when a garage, carport, or covered parking structure is demolished in conjunction with the construction of an ADU or converted to an ADU.
Additional Imperial Beach ADU Regulation Resources
City of Imperial Beach – Handout – What Triggers a Coastal Permit for ADUs?
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About SnapADU
Since 2020, we’ve focused exclusively on designing, permitting, and building over 100 ADUs in San Diego. Our deep experience means we catch what others might miss, and our in-house team ensures every promise is delivered.
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