ADU builders and rules in Imperial Beach

Imperial Beach ADU rules

The city's ADU page sets out what Imperial Beach allows by zone and the size, height and setback standards it applies. Its Planning Division FAQ says ADUs are generally allowed in zones that allow residential development, and points to the ADU ordinance the city adopted in 2021, Ordinance 2021-1204.

How many ADUs can you build in Imperial Beach?

On a lot in the single-family R-1-6000 or R-1-3800 zones, the city's zoning table allows one new detached ADU, plus one attached ADU or one conversion of existing space (not both), plus one junior ADU inside the house. In the R-3000-D and R-3000 two-family zones, the same detached and attached-or-conversion pair applies, and the R-3000 zone adds the multifamily options below.

On a lot with an existing apartment building in the R-3000, R-2000 or R-1500 zones, you can add up to eight detached ADUs, but no more than the number of existing units, and convert space inside the building into ADUs for up to 25% of the existing units, with at least one allowed. A lot with a proposed multifamily building can add up to two detached ADUs.

Parking is rarely an issue here. The city's housing plan found that 99% of developable parcels sit within half a mile of a major or high-frequency transit stop, and state law bars ADU parking requirements within a half-mile walk of public transit. If you're weighing a junior ADU or a garage conversion, see our junior ADU guide and garage conversion ADU guide. The state rules behind all of this are in California ADU laws.

The coastal permit for an Imperial Beach ADU

This is what sets Imperial Beach apart. According to the city's housing plan, 87% of Imperial Beach lies within the Coastal Zone. The city's coastal permit handout for ADUs says you need a coastal permit in the Coastal Zone for:

• a new attached ADU,
• a new detached ADU,
• converting permitted non-habitable space, such as a garage, storage room or patio cover, into an ADU, and
• converting a garage into a junior ADU.

To check your lot, open the city's parcel viewer, choose “Themes” and turn on “Coastal Zone Jurisdiction.” The color tells you who issues the permit:

The handout says the coastal permit must be approved before you apply for the building permit, though concurrent planning and building review is available if you ask staff. Review takes 30 calendar days from the date you pay, and the city's coastal permit for an ADU costs $1,000, with more due if multiple reviews are needed.

Blue-zone projects go through the Commission's own process. In July 2026, for example, the Commission's San Diego district reported a waiver for an 8th Street lot converting a roughly 784 sq ft detached garage into two ADUs of about 374 sq ft each. The report notes the site is within half a mile of a bus stop, so state law required no new parking and no replacement for the garage.

Imperial Beach pre-approved ADU plans

Imperial Beach offers one pre-approved ADU plan: a 600 sq ft detached ADU plan set the city posts as a PDF, drawn to the 2025 California building codes. A companion checklist guidance document walks you through the blanks you fill in: plot plan, owner and project details, pervious and impervious area tables, stormwater measures, roofing, insulation and energy features.

You still have to supply site-specific items: Title 24 energy calculations, a stormwater quality management plan, signed truss calculations, a construction waste management plan, and either a soils report or the city's request to waive one. A solar PV system is a deferred submittal. A coastal permit still applies if your lot is in the Coastal Zone. Under state law, cities must run a pre-approval program for ADU plans and act on applications that use one within 30 days. Questions go to Associate Planner Ryan Pua at 619-628-1356.

Imperial Beach's own plan is a single size. If you want something larger, see our pre-approved ADU plans in San Diego guide and attached vs. detached ADUs, and ask the city whether it will accept another agency's plans.

Imperial Beach ADU fees

The master fee schedule prices building permits on valuation. At a $100,000 valuation the permit and inspection fee starts at $2,295 plus $14.80 per added $1,000, and plan check starts at $1,691 plus $2.11 per added $1,000. By that schedule's arithmetic, a $200,000 valuation works out to about $3,775 for the permit and $1,902 for plan check. The city decides the valuation, and the schedule may be updated, so ask for an estimate.

The ADU coastal fee is lower than the $2,323 minimum the same schedule lists for other administrative coastal permits. The city's housing plan says the South Bay Union School District serves Imperial Beach, California American Water, a private company, supplies its water, and the city runs its own sewer collection system tied into the regional Metro system. Older students attend Sweetwater Union schools such as Mar Vista High, which is why that district's fee applies. For the whole budget, see what an ADU costs in San Diego or try the ADU cost calculator.

Getting an Imperial Beach ADU permit

Imperial Beach takes building permits entirely online through its Citizen Self-Service portal. You create an account, then apply, upload plans and pay there. City Hall, at 825 Imperial Beach Blvd., is open Monday through Thursday, 7:30 a.m. to 5:30 p.m.; staff help with permits from 7:30 to 9:00 a.m. and 3:30 to 5:00 p.m. Coastal permits go through the same portal under Apply, Plans, then the planning permit type that fits your project.

For ADU questions, the city's ADU page lists City Planner Arturo Ortuño at 619-628-0858 and Associate Planner Ryan Pua at 619-628-1356. Once your building application is complete, state law gives the city 60 days to approve or deny it.

ADU building has grown. The housing plan counted 12 ADUs in 2019 and 22 permitted in the first 10 months of 2020, and set a goal of 200 ADUs from 2021 to 2029. Before you hire, read how to hire an ADU contractor, check a contractor's license, and compare verified ADU builders in San Diego County. If you plan to rent the unit, see ADU rental income in San Diego.

Common questions