Inside the city limits, the City's Development Services Department issues building permits, and you apply online. Every ADU or junior ADU needs a building permit, with no exemptions. The City runs its own ADU Home Density Bonus Program, which can allow a total of four, five or six ADUs and JADUs on a single-family lot, depending on its size, when some are kept affordable. It also lets you turn an ADU into a condominium and sell it apart from the house, and near the coast its newest ADU rules wait for the Coastal Commission.
Who issues permits here, and how does plan check run?
The City's Development Services Department reviews plans and issues building permits inside the city limits. You need a building permit to create any ADU or JADU, and the City lists no exemptions. Depending on how many homes the project creates, the City files it as a combination building permit, the record type it uses for houses, ADUs and duplexes, or as a building permit.
You apply digitally, through an Online Permitting Account on the department's application portal, and choose Building Construction for a new project. For each ADU or JADU the City's minimum set is a site plan with a vicinity map, floor and roof plans, elevations and sections where they apply, structural plans and calculations, and Title 24 energy calculations. Add the general application form, the water meter data card and the stormwater checklist.
The City's submittal manual for houses, duplexes and accessory structures says which forms and plans each kind of project needs. Staff prescreen what you upload. Once the package is complete and the plan check fees are paid, the project counts as complete and goes into plan check. If a building on the site is 45 years old or older, include the County Assessor's building record and a photo survey with the application.
Plan check runs in cycles. Each review discipline writes its own list of issues, and you cannot upload corrections until every discipline has finished its cycle. Your answers to all of them then go back as one resubmittal, and the recheck starts once every document the City asked for is uploaded. If you disagree with a completeness call or a review comment, the manual lets you ask for a second opinion.
State law puts the City on a clock for ADUs. It has 15 business days to tell you in writing whether an ADU application is complete, and 60 days from a complete application to approve or deny it when a house already stands on the lot.
For how long each step takes right now, the department posts a weekly snapshot of average days for intake screening, first reviews, rechecks and permit issuance, beside a dashboard of its permit data. Simpler projects can go through Rapid Review at no extra cost, and Express plan check is offered for most disciplines for an added fee.
What your lot allows starts with its zone, which the City's ZAPP map shows. The single-family RS zones set minimum lot areas from 5,000 square feet in RS-1-7 up to 40,000 in RS-1-1, with side setbacks from 4 to 10 feet. In RS-1-1 to RS-1-7, height starts at 24 feet over the setback line and rises along an angled plane to 30 feet; the plane leans in at 45 degrees on lots under 75 feet wide and 30 degrees on lots 75 to 150 feet wide. RS-1-8 to RS-1-14 allow up to 35 feet.
Here is what that means for the projects homeowners bring most often.
- An ADU or JADU: the permit above. Building from one of the preapproved plans the City accepts brings a 30-day review, and in the Coastal Overlay Zone most ADUs also need a Coastal Development Permit.
- A kitchen or bath remodel: a No-Plan Building Permit when you change no structure, framing or exterior walls and add no plumbing fixtures, on a building that was permitted and passed its final inspection. A building 45 years old or older can still need historic review.
- A one-story addition or remodel of a house or duplex: a plan set, the stormwater checklist and the Energy Code forms, historic review when a building on the site is 45 or more years old and the work touches the outside, and fire-resistant construction in a Very High Fire Hazard Severity Zone where the bulletin says it applies, which depends on when the house's own permit application was complete.
- A new house: a building permit with full plans, built inside the zone's height and angled envelope. West of Interstate 5 the 30-foot Coastal Height Limit also applies, and in the Coastal Overlay Zone a Coastal Development Permit usually does.
Where do the City's ADU rules differ from state law?
State law sets a floor for ADUs across California, and the ADU section of the City's Municipal Code builds on it. The table gives the City's rules for a lot with a house, with the state floor beside them where it helps. Some of these rules are not yet in effect in the Coastal Overlay Zone; the coastal section below explains.
| Rule | In the City of San Diego |
|---|---|
| Units on a single-family lot | The house, one attached or detached ADU, one ADU carved out of the house or an existing accessory structure, and one JADU. Guest quarters and non-habitable accessory buildings can be added on top where the zone allows them. |
| ADU size | At least 150 and at most 1,200 square feet of gross floor area for a new attached or detached ADU. An ADU made inside the house or an existing accessory structure has no maximum and may add up to 150 square feet only for its entrance. |
| JADU size and place | 150 to 500 square feet, inside the house or its attached garage, with its own outside door and a kitchen or efficiency kitchen. A JADU does not count toward the lot's floor area ratio. |
| Floor area ratio | A new ADU counts toward the zone's floor area ratio. One ADU of up to 800 square feet is allowed even if it takes the lot over the limit, in line with the state's protection for an 800-square-foot ADU. |
| Height | The overall height limit of the zone and any overlay zone. On a lot zoned for single dwellings only, a detached ADU may have up to two stories. State law sets floors of 16 feet for most detached ADUs, 18 feet within a half mile of major transit, and 25 feet or the zone's limit for an attached ADU. |
| Side and rear setbacks | None for an ADU 16 feet tall or less outside a fire hazard zone, though Building Code fire separation can still push it back. Taller than 16 feet beside a residential lot: 4 feet, or the zone's setback if that is less. In a Very High Fire Hazard Severity Zone: 4 feet at any height, and the Fire Code Official can ask for more. The code says High or Very High, but the City's adopted map shows only Very High zones. State law lets a city ask for no more than 4 feet. |
| Front and street side setbacks | The zone's front setback, except that one ADU of 800 square feet or less can sit in it when it is the only attached or detached ADU on the lot. On the street side of a corner lot, 4 feet or the zone's street side setback, whichever is less. Decks, balconies and outside stairs keep to the zone's setbacks. |
| Parking | None for an ADU or JADU across most of the City, and a garage or carport converted or removed for one does not have to be replaced. The exception is the Beach Impact Area outside a transit priority area: there each new ADU needs one space unless it is 500 square feet or less, attached, in a designated historical district or a residential permit parking district, or within a block of a car share vehicle, and a garage, carport or covered space converted or torn down there must be replaced. Under the bonus program, each affordable and bonus ADU outside a transit priority area needs one space. |
| Driveway | If an ADU or JADU leaves an existing driveway too short for the City's parking standards, the driveway has to be closed. The City's ADU page gives the example of a driveway under 18 feet long from the back of the sidewalk. |
| Owner occupancy | Not required for an ADU. For a JADU, only when it shares a bathroom with the house, and then the owner lives in the house or the JADU. |
| Rentals | An ADU or a JADU cannot be rented for less than 31 consecutive days, so no vacation rental. |
| Fire sprinklers | Needed only when the main house is required to have them, and building an ADU doesn't force them into the house. Every affordable and bonus ADU under the bonus program needs them. |
| ADU Home Density Bonus | Extra ADUs when some are deed-restricted as affordable through an agreement with the San Diego Housing Commission. Inside a Sustainable Development Area, a set walking distance from a major transit stop, each affordable ADU brings one bonus ADU; elsewhere the most is one of each. Not offered in the RS-1-1 to RS-1-4 or RS-1-8 to RS-1-11 zones unless the lot sits in a High or Highest Resource opportunity area and is planned as residential. |
| Most ADUs and JADUs on a single-family lot | Four on 8,000 square feet or less, five on 8,001 to 10,000, and six on 10,001 or more, every ADU and JADU counted, bonus units included. A lot of exactly 10,000 square feet gets five. Environmentally sensitive land is left out of the lot area. |
| Bonus ADUs in fire zones | The lot has to face an improved public street with at least two evacuation routes, and cannot be on a cul-de-sac or a site with only one way in and out. This applies in the City's Very High fire zones. |
| Selling an ADU separately | A new or existing ADU can become a condominium and be sold apart from the house: through the City's subdivision rules, after its final inspection, with every lienholder's written consent, and offered first for 30 days to buyers who will live in it. An ADU assisted by the Housing Commission or a rent-restricted ADU cannot be sold this way while its restriction runs, and a JADU never can. The code doesn't bar a market-rate bonus ADU, but the Housing Commission holds a deed of trust on a bonus project and has to consent first. |
Under the bonus program, an affordable ADU stays deed-restricted for at least 10 years when it is rented to a very low or low income household, and at least 15 years for a moderate income household.
A few of the City's own documents haven't caught up with these rules:
- The City's ADU page mentions parking in the Beach Impact Area only for garage conversions. The code requires a space for a new ADU there too, so confirm at intake whether your lot is in the Beach Impact Area and a transit priority area.
- The Municipal Code and its JADU agreement still say the owner must live on the lot with every JADU, and that a JADU has no rental limit. State law changed both on January 1, 2026, and the City's bulletin follows it. Ask at intake which version of the agreement the City will record for you.
- The City's ADU page still gives 15 years of affordability at every income level. The code cut the very low and low income term to 10 years in 2022.
- The City's ADU page says ADUs must keep to the front setback, leaving out the 800 square foot exception in the code. Ask at intake how the City measures the 800 square feet: the code says gross floor area, state law interior livable space.
- The City's ADU page and its sprinkler bulletin also ask for sprinklers when one detached building holds three or more ADUs. HCD told the City in October 2025 that this goes beyond state law, so confirm the City's position at intake if you plan that.
- The City's ADU page says bonus program ADUs can't be sold separately. The code bars only Housing Commission-assisted and rent-restricted ADUs, so check with the City and the Housing Commission before you plan a sale.
- Information Bulletin 400's table reads as if a lot of exactly 10,000 square feet gets six units. The code's table says five.
Can you build from a preapproved ADU plan here?
Yes, from another agency's set. The City's ADU page lists no plans drawn by the City itself, and it accepts three outside sets: the County of San Diego's standard ADU plans, Chula Vista's standard ADU plans and Encinitas's permit-ready ADU plans.
An application built on one of them gets a 30-day review, and the project still has to meet the Municipal Code's development rules for your lot. The plans have to be drawn to the codes in force on the day you submit, and you ask the plan's provider what a license to use it costs.
Designers can also ask the City to preapprove their own plans for others to use, through the master plan process in Information Bulletin 114a. Once a plan clears, the City posts it on its website with the designer's contact details beside the others.
Coastal, fire, historic and hillside rules
The City's Coastal Overlay Zone map shows if your lot is in the zone, and if so, in the appealable or the non-appealable part. Inside the zone, an ADU or JADU needs a Coastal Development Permit unless it stays entirely within the existing house without adding habitable area or converting non-habitable space, and a JADU that meets the code's exemptions can do without one. In the non-appealable area the City can issue that coastal permit as a building permit once its findings are made. If the project is only an ADU or a JADU, state law has barred any appeal of the City's coastal permit to the Coastal Commission since October 10, 2025, and gives the City 60 days to act on a complete application, with no public hearing required. If you build a new house or other work along with the ADU, the rest of that permit can still be appealed in the appealable area.
Coastal lots also have to meet the code's wetland, coastal bluff and beach rules, and its sea level rise rules where they apply. ADU projects there follow the setback and landscape rules of Housing Action Package 1.0, which the Coastal Commission certified in September 2024. The City's 2025 ADU amendments (O-21989) and its 2026 code update (O-22109) do not apply in the Coastal Overlay Zone until the Commission certifies them, and the City's code updates page expects the 2025 package to be approved there in 2026.
The earlier packages do apply there. Housing Action Package 2.0 has been in effect on coastal lots since March 11, 2026, and the City's 2024 code update since September 10, 2026. So a coastal lot follows the bonus program as it stood before the 2025 amendments: no cap by lot size, no set limit on bonus ADUs inside a Sustainable Development Area beyond the zone's floor area, height and coverage, and none of the 2025 sprinkler, parking, street access or fee rules. Selling an ADU as a condominium isn't available there yet.
Information Bulletin 400 (January 2026) still lists Housing Action Package 2.0 as not in effect on the coast, so ask the City at intake which version of the rules it is applying to your lot.
Remodeling near the coast has its own trigger. In the Coastal Overlay Zone, an improvement to an existing building loses its exemption from a Coastal Development Permit when half or more of the exterior walls are demolished or removed. The City counts walls in linear feet, floor by floor, includes walls taken out by accident, and treats a wall that a new addition wraps as removed.
Between the ocean and Interstate 5, as the freeway ran on January 1, 1971, no building or addition may rise above 30 feet, apart from four mapped areas. San Diego voters set that Coastal Height Limit with Proposition D in 1972, and only another public vote can change it, so it caps second stories and new houses there whatever the zone allows.
For fire, the City adopted the State Fire Marshal's 2025 recommended map and added areas its own fire department found at risk, designating all of them Very High Fire Hazard Severity Zones on one City map. The Council adopted Ordinance O-21992 on July 29, 2025, and the map took effect on August 30, 2025. Under state law the City can add to the state's zones but never lower them.
If any part of your lot falls inside a mapped zone, the City applies the state's wildfire building standards to new buildings, to additions and to exterior alterations that touch the regulated building features, and 100 feet of defensible space plus the City's brush management rules apply. Zone 0, the 5 feet around a building, has to stay clear of plants and combustible materials, with limited exceptions, for any new structure that applied for a building permit on or after February 28, 2026. For existing homes the City starts on February 28, 2027 and phases in full compliance by February 28, 2029.
Before the City issues a construction permit on any parcel with a structure 45 years old or older, its staff screen the site for historical significance. Interior work, and electrical, plumbing or mechanical permits that change nothing outside, are exempt. You send photographs and the County Assessor's building record, and the City puts the usual review at ten business days for a ministerial project and 20 for a discretionary one. If staff find nothing, the parcel skips further historical review for five years.
If staff find a resource may exist and the project would substantially alter it, a site-specific survey follows, and Information Bulletin 580 asks for a research report when the project cannot meet the Secretary of the Interior's Standards. A project that meets the Secretary of the Interior's Standards can go ahead without a designation. One that does not can be sent to the Historical Resources Board, and a designated site needs a Site Development Permit for a substantial alteration.
The Municipal Code treats land as steep hillside when its natural slope is 25 percent or more across at least 50 feet of elevation, or 200 percent or more across at least 10 feet. If any part of your lot holds steep hillsides or other environmentally sensitive lands, such as sensitive habitat, coastal bluffs or a flood hazard area, those lands' rules apply to the whole lot.
Building into those lands takes a discretionary permit on top of the building permit: a Neighborhood Development Permit for one house on a lot of 15,000 square feet or less, or a Site Development Permit on larger lots and, at any lot size, on sensitive coastal bluffs and coastal beaches. Outside the multiple habitat planning area (MHPA) and the Coastal Overlay Zone, steep slopes stay natural except as needed to give a development area of up to 25 percent of the lot. A project that keeps out of the sensitive lands can be exempt from those permits if it meets the code's conditions.
Two more rules follow the slope. On a lot where at least half of the front 50 feet slopes 25 percent or more, the RS zones let the front setback drop to 6 feet. Under the ADU bonus program, environmentally sensitive land is left out of the lot area that sets the unit cap and the floor area ratio.
Which fees apply, and where are the schedules?
The City publishes its construction permit fees in Information Bulletin 501 and links its other fee bulletins from its fees page. Fees fall due at different points: some when you submit, some during review, some at issuance and some during inspection. Development impact fees are due before the final inspection. The bulletin is revised often, so check the current version before you budget.
- Development impact fees. The Municipal Code exempts every JADU and any ADU under 750 square feet of gross floor area. The first two ADUs on a lot are exempt at any size, counting the two smallest when there are more, unless they are built under the City's SB 9 rules and exceed 750 square feet. Any ADU is exempt when the owner records an affidavit to live on the property for three years from permit issuance.
- School fees. The school district sets them and you pay the district directly; the City measures the assessable space, and you upload the district's receipt when the permit is issued. Residential work that adds 500 square feet or less is exempt, and so is a new detached ADU or JADU with less than 500 square feet of assessable space.
- General Plan Maintenance Fee. It has applied to every ADU and JADU since August 9, 2022. The City collects it once per project when you apply, and it is not refundable.
- Water and sewer capacity fees. The City collects them for its Public Utilities Department and works them out during plan review by equivalent dwelling units, and the water fee can be deferred. The San Diego County Water Authority can add its own capacity fee when a new meter goes in.
- What state law allows for utilities. An ADU built inside existing space, or a JADU, is not a new residential use for connection fees or capacity charges unless it is built with a new house, and for other ADUs the charge has to match the ADU's burden, by size or plumbing fixtures compared with the house. An ADU legalized under Information Bulletin 242 pays no water or sewer capacity fees.
- More than one ADU, or the bonus program. A project with more than one ADU pays the Regional Transportation Congestion Improvement Program fee, bonus projects pay a Community Enhancement Fee set by City resolution, and ADUs that bring a lot to 10 or more homes (five or more in the Coastal Overlay Zone) fall under the inclusionary housing rules.
How many ADUs the City permits
Each year the City reports the housing permits it issued to the state's housing department. It reported permits for 216 ADUs in 2018 and for more than 2,000 in each of 2024 and 2025.
- 2162018
- 6272019
- 4912020
- 8702021
- 6622022
- 1,9132023
- 2,2812024
- 2,1652025
These count building permits issued, not ADUs finished, as the City reported them to HCD in its housing element annual progress reports (Table A2, ADU category), by reporting year; the 2023 figure includes 4 units whose permits are dated 2022. HCD's form has no separate junior ADU category, so any JADUs the City reported sit inside these figures and cannot be shown apart.
Recent changes in the City
Changes to the City's permit rules since 2024, and the state law due on January 1, 2027, newest first.
The state's floor rises to two new detached ADUs of up to 800 square feet, beyond the code's one attached or detached ADU. Since the City already waives its own impact fees on a lot's first two ADUs, SB 1117 adds little here; see our 2027 guide.
The City's 2026 Land Development Code Update, Ordinance O-22109, took effect outside the Coastal Overlay Zone. It amended the ADU section (141.0302) and the development impact fee section (142.0640), and inside the Coastal Overlay Zone its changes wait for Coastal Commission certification. The signed ordinance records the Council's adoption at its June 8, 2026 meeting and the mayor's approval on June 15, 2026, the date the Municipal Code gives.
The edition of Information Bulletin 242 in effect until this day was replaced by the May 2026 edition: the City's streamlined permit for an ADU or JADU built without a permit before January 1, 2020, under AB 2533 (signed September 28, 2024).
The Coastal Commission's certification of Housing Action Package 2.0 was reported, and the City's code updates page lists the package as in effect in the Coastal Zone from that day. Information Bulletin 400 still lists it as not in effect there; the coastal section above shows both.
Ordinance O-22042, the City's adoption of the 2025 California Wildland-Urban Interface Code, took effect. In the City's Very High Fire Hazard Severity Zones, Zone 0 rules now apply to new structures applying for a building permit, and they reach existing structures on February 28, 2027.
HCD found the City's 2025 ADU ordinance out of line with state ADU law on four points: fire sprinklers in attached groups of ADUs, size limits on ADUs detached from multifamily buildings, wording that mixes setbacks with fire separation distance, and tenancy in common terms for sales by nonprofits. It asked for the City's written reply by November 5, 2025.
The City's 2025 fire hazard severity zone map took effect under Ordinance O-21992, which the Council adopted on July 29, 2025. It takes in the zones the State Fire Marshal recommended on March 24, 2025, plus more areas the City found at risk, all as Very High zones.
The City's 2025 ADU and JADU amendments, Ordinance O-21989, took effect outside the Coastal Zone. Its sources give two adoption dates: the City's code updates page and the clerk's certificate say the Council adopted it on July 22, 2025, while HCD's review letter and the Municipal Code's history note give July 23, 2025, which the ordinance records as its date of final passage, the day the mayor's signed copy came back.
The Coastal Commission certified the ADU rules of Housing Action Package 1.0, so ADU projects in the Coastal Overlay Zone now follow its setback and landscape rules.
How BHI approaches a City of San Diego project
What we look at first on a lot inside the City's limits.
Inside the City we start with the lot's overlays: whether it falls in the Coastal Overlay Zone, where the 2025 ADU amendments still wait on the Coastal Commission; whether a house on it is 45 years old or older and needs the historic screening; and whether the bonus program or a Very High fire zone changes what fits. Our City permits run from custom homes and additions in Black Mountain Ranch to a kitchen and bath remodel in Mira Mesa. Book a call to talk through your lot.
Next steps
Check your lot against the City's rules, price the work, then read what fits your project.