ADU Pass
San Ysidro
San Diego County portion
Also in: No County
ADU Pass helps homeowners in San Ysidro, San Diego County, California navigate the permit paperwork for building an accessory dwelling unit. This area covers 1 ZIP code.
Map
ADU details
ADU legality: allowed
ADUs are by-right in San Ysidro under City of San Diego DSD jurisdiction. Sole gating overlay is the Coastal Overlay Zone on the Tijuana Estuary frontage — most San Ysidro parcels are outside it.
Cost scenarios
| Scenario | Sq ft | Permit | Build | Total |
|---|---|---|---|---|
| minimum | 150 | $6,500 | $75,000 | $81,500 |
| 600 | 600 | $8,200 | $300,000 | $308,200 |
| midpoint | 675 | $8,800 | $337,500 | $346,300 |
| 1000 | 1,000 | $18,500 | $500,000 | $518,500 |
| maximum | 1,200 | $21,000 | $600,000 | $621,000 |
Fee breakdown (as of 2026-04)
Permitting process
- Pre-application research / virtual appointment (~7d)
Optional but recommended — book a free DSD virtual appointment via sandiego.gov/development-services/virtual-appointments to confirm zone, San Ysidro Community Plan land-use designation, Coastal Overlay status, and whether parcel sits in a Sustainable Development Area for Bonus ADU eligibility - Plan submittal via Accela Citizen Access (DSD portal) (~3d)
All ADU permits must be submitted online at aca-prod.accela.com/SANDIEGO. Required: General Application (DS-3032), Water Meter Data Card (DS-16), Storm Water Applicability Checklist (DS-560), site / floor / roof / elevation / section plans, structural calcs, Title 24 energy calcs - First-cycle plan review (DSD) (~50d)
Multi-discipline review (Building, Land Development, Fire, MEP, Energy). Custom-plan ADUs: ~45-60 days first cycle. Pre-approved plans (City catalog plus accepted Chula Vista / SD County / Encinitas plans): 30-day ministerial review window per IB-400 - Corrections / resubmittal cycle (~30d)
Applicant addresses plan-review comments. Two cycles is typical for custom plans; one cycle sometimes sufficient - Second-cycle review (if needed) (~21d)
Final review when corrections are comprehensive. Pre-approved plans typically skip this step - Coastal Development Permit (only if in Coastal Overlay Zone)
Required for ADUs in San Ysidro's Coastal Overlay fringe (Tijuana Estuary frontage) unless the ADU is wholly contained in the existing primary structure. CDP review adds 60-120 days and may require Coastal Commission action - Permit issuance — fees paid via Accela (~5d)
Plan-check (65% of permit fee, due at submittal) plus permit, GPM Fee, school fees, applicable DIF/RTCIP. Permit downloadable from Accela - Construction inspections
Foundation, framing, MEP rough, insulation, drywall, final. Inspections scheduled through Accela; SDG&E and water-district sign-offs needed before final
Viability (permitted uses)
- Long-term rental: yes Long-term rental (30+ days) is by-right per state ADU framework. AB 976 permanently ended owner-occupancy requirements (effective 2024-01-01).
- Short-term rental: with-restrictions City of San Diego STR Ordinance (effective 2023-05-01) requires a Short-Term Residential Occupancy (STRO) license. Tier 3/4 licenses are capped citywide and have a wait list; ADU rentals under 30 days require an STRO license separate from the ADU permit.
- Office rental: no ADUs are dwelling units by definition (SDMC §141.0302). Renting to a non-residential office tenant is not permitted; converting an ADU to office space requires zoning change.
- Home office: yes Owner home-occupation use within an ADU is permitted in residential zones, subject to standard SDMC §141.0504 (Home Occupations) limits on signage, customer traffic, and employee count.
- Studio / workshop: yes Personal artist studio / workshop is a permitted accessory residential use.
- Agriculture: with-restrictions San Ysidro residential zones permit limited urban agriculture (community gardens, small chicken keeping per SDMC §141.0501). ADU may not be used as agricultural storage / processing outside the dwelling-unit envelope.
- Relative support: yes Family / multigenerational occupancy is by-right; both ADU and JADU options work for elderly parent or adult-child housing.
Incentives
Pre-approved plans Pre-approved plans
Contacts
Staff: DSD ADU Information (ADU Coordinator (general inbox)) ADUInfo@sandiego.gov, City Planning Department (San Ysidro Community Plan) (Planning Department main contact) planning@sandiego.gov, San Ysidro Community Planning Group (Recognized community planning group (recognized 1967); reviews discretionary projects in San Ysidro) planning@sandiego.gov
Contractor directory (3)
Scope: metro, 30 mi radius.
General Contractor (3)
- Quality Builder ADU specialist
+1-858-286-8045 · website - OneStop ADU ADU specialist
website - SnapADU ADU specialist
website
Utilities
- Water: City of San Diego Public Utilities Department (most of San Ysidro 92173) — northern Otay Mesa border parcels may fall under Otay Water District · 30d connect · $5,500
ADUs under 750 sqft do not require a separate water service per SB 13. City of San Diego water-meter sizing reviewed via DS-16 form. - Sewer: City of San Diego Public Utilities Department · 30d connect · $6,500
Capacity / connection fees only apply to ADUs ≥750 sqft per SB 13. - Electric: San Diego Gas & Electric (SDG&E) — sole regulated electric provider in San Diego County · 21d connect · $1,800
Title 24 2025 requires solar PV for newly built ADUs; pair with SDG&E NEM application. - Gas: San Diego Gas & Electric (SDG&E) · 21d connect · $1,500
California's all-electric stretch (CALGreen Tier 2) applies in some plan-approved cases; gas service still permitted on standard ADUs.
Property values & taxes
Construction timeline
Realistic total: best 9mo · typical 14mo · worst 20mo
Custom-plan ADU averages 217 days permit + ~7 months construction = ~14 months realistic. Pre-approved plans cut permit time by ~3 months.
Modular pathway inspectors are experienced with modular
Financing
State ADU loans:
- CalHFA ADU Grant Program up to $40,000
- HCD ADU Funding index
Insurance impact
HOA prevalence & preemption
California has the strongest statewide HOA-preemption regime in the US for ADUs: AB 670 (2019) voided ADU-prohibiting covenants on single-family residential lots, and AB 3182 (2020) extended the preemption into Davis-Stirling (Civil Code §§ 4740 / 4741). HOA presence in San Ysidro is moderate — older single-family neighborhoods west of Beyer Blvd are largely non-HOA, while newer southeast-San Ysidro subdivisions (Las Americas, Ocean View Hills border) have HOAs.
Regulatory overlays (3)
- coastal-commission
City of San Diego Coastal Overlay Zone covers the northwestern San Ysidro fringe abutting Tijuana River National Estuarine Reserve. CDP required there unless ADU is wholly within the existing primary structure (per IB-400 + ordinances O-21618, O-21758, O-21836, O-21989 awaiting Coastal Commission certification). Most San Ysidro residential parcels east of I-5 are outside the overlay. - flood-zone
FEMA SFHAs run along the Tijuana River and several South Bay drainages within 92173. Elevation certificates required for floodplain parcels. - airport-noise-zone
Brown Field Municipal Airport (KSDM) noise contours touch portions of eastern San Ysidro / Otay Mesa border. ALUCP review may apply.
Technical envelope (climate & building code)
Climate & energy code
Building code
Amendments:
- Amendment
- Amendment
Contractor market (aggregate)
Legal history (timeline)
Current ordinance: San Diego Municipal Code §141.0302 (Accessory Dwelling Units), adopted 2017-01-01, last amended 2024-09-12
- 1957-09-13 — South Bay Annexation — San Ysidro joins City of San Diego (annexation)
After San Ysidro voters approved annexation 1957-07-16, the City of San Diego annexed a 21.5 sq mi area extending to the international border (the 'strip annexation' via a 300-foot underwater Coronado Bay corridor).
Effect: From this date forward, all land-use, zoning, building, and ADU permitting in San Ysidro has been governed by the City of San Diego — not by any separate municipality. There is no 'City of San Ysidro'. SDMC and IB-400 control. - 1974-01-01 — San Ysidro Community Plan adopted by City Council (community-plan)
First adoption of the San Ysidro Community Plan, which sits beneath the City's General Plan as the area-specific land-use blueprint.
Effect: Established the residential / commercial / mixed-use framework that ADU permitting later layered onto. Community Planning Group recognized in 1967. - 2016-11-15 — San Ysidro Community Plan Update adopted (community-plan)
Comprehensive update covering Land Use, Mobility, Urban Design, Economic Prosperity, Public Facilities, Recreation, Conservation, and Historic Preservation elements. Coastal Commission certified the LCP amendment for the small coastal-zone fringe.
Effect: Current land-use blueprint for the community. ADU rules continue to come from citywide SDMC §141.0302; the community plan governs zone designations on individual parcels. - 2020-06-30 — ADU Bonus Program enacted (SDMC §141.0302(e)) (city-ordinance)
City Council adopted the Bonus ADU Program permitting one bonus market-rate ADU per affordable ADU set aside (10-yr term) within Sustainable Development Areas (transit proximity).
Effect: Made multi-ADU projects feasible on transit-served single-family parcels. San Ysidro's transit corridor along Beyer Blvd / I-5 / Blue Line trolley qualifies large portions of the community. - 2024-08-05 — SDMC §141.0302 amended by Ordinance O-21843 (effective 2024-09-12) (city-ordinance)
Amendments to the ADU section codified state-law conformance updates and refined development standards. Companion ordinance O-21836 (adopted 2024-07-22, effective 2024-10-05) addressed coastal-overlay ADU rules pending Coastal Commission certification.
Effect: Current operative version of §141.0302 for non-coastal San Ysidro parcels. IB-400 was reissued November 2024 to reflect these changes. - 2025-08-01 — ADU Bonus Program reform — height and density limits (city-ordinance)
Council adopted reforms limiting ADU Bonus Program projects in single-family zones to two stories, capping bonus units to 4-6 per parcel, instructing staff to remove eligibility from RS zones with ≥10,000 sqft minimum lot size, and adopting AB 1033 condo-conversion authority.
Effect: Reduces large-scale Bonus ADU developments in low-density San Ysidro RS-1 areas while preserving the program for transit-proximate parcels. Community Enhancement Fee newly required on bonus / affordable ADUs under 750 sqft. - 2025-09-01 — IB-400 republished (current revision January 2026) (regulatory-guidance)
DSD reissued Information Bulletin 400 (Accessory Dwelling Unit / Junior Accessory Dwelling Unit) to incorporate 2024-2025 ordinance changes and the new pre-approved-plan 30-day review window.
Effect: IB-400 is the operational permitting reference applicants must follow for any ADU in San Ysidro. Pre-approved plans (City catalog plus accepted Chula Vista, County, and Encinitas plans) trigger the 30-day review.
Known issues (1)
- policy-review — ADU Bonus Program reforms adopted 2025 are still being implemented; staff was instructed to bring back additional changes (RS-zone exclusion) within 60-90 days of the August 2025 vote. Bonus-eligibility rules in San Ysidro RS-1 areas may shift again before late-2026 applications submit.
San Diego County — county ADU rules and overlays
County ADU ordinance
San Diego County regulates ADUs on parcels in the unincorporated county under Title 6 of the County Code (Zoning Ordinance), Sections 6156.x. The county's ADU framework layers on top of California Government Code sections 65852.2 (ADU) and 65852.22 (JADU), which preempt many local standards statewide; the county ordinance fills in the locally-controlled parameters (setbacks, design standards, parking in non-transit unincorporated areas, fire-safe design in VHFHSZ) that state law leaves to local choice. The current ordinance reflects amendments adopted 2020 (Ord. No. 10693) and 2023 (Ord. No. 10749) to conform with AB 68 / AB 881 (2019), AB 976 (2019 owner-occupancy elimination through 2024), SB 13 (2019 fee reductions), AB 2221 / SB 897 (2022 design/permit clarifications), and AB 1033 (2023 condo-ADU optional program; San Diego County has not opted into AB 1033 condo separation as of 2026-04-20). The county permits up to one ADU plus one JADU per single-family parcel by right, and the state-mandated two ADUs per multifamily lot; parking is not required on ADUs within 1/2 mile of transit. The county's distinct contributions on top of state law are the fire-hardening / defensible-space design standards for ADUs sited in Very High Fire Hazard Severity Zones, the airport-noise compatibility review for ADUs within Airport Land Use Compatibility Plan (ALUCP) zones, and the Coastal Development Permit (CDP) requirement for ADUs in the county's certified Local Coastal Program (LCP) jurisdiction.
- San Diego County Code of Regulatory Ordinances Title 6 (Zoning) — Accessory Dwelling Unit provisions
- PDS ADU Technical Bulletin and applicant handouts
- Ordinance No. 10693 — 2020 ADU ordinance conforming to AB 68 / AB 881 / SB 13
- Ordinance No. 10749 (approximate) — 2023 ADU ordinance update for AB 2221 / SB 897 / AB 1033
State-floor overlay: California state law (Gov. Code 65852.2, 65852.22) preempts most local ADU regulation. The state sets ministerial-approval requirements, caps fees, mandates 60-day permit review, forbids local owner-occupancy requirements through 2024 (extended effectively through AB 976 / subsequent amendments), sets minimum allowed sizes (850 sqft one-bedroom, 1000 sqft two-bedroom), forbids parking requirements within 1/2 mile of transit or on replacement-covered-parking ADUs, and caps impact fees at zero for ADUs under 750 sqft. San Diego County's ordinance reiterates and applies these floors, adding only the locally-controlled fire, airport, and coastal overlays. Where a project is in a VHFHSZ or coastal-commission jurisdiction, state ADU preemption still applies to the ADU allowance itself but does not preempt the county's separate fire and coastal authority over site-design standards.
County regulatory overlays
San Diego County administers or co-administers several overlay regimes that materially affect ADU siting on unincorporated parcels: (1) the California Coastal Commission's jurisdiction along the coastal zone (a narrow band up to 5 miles inland in some places), implemented through the county's certified Local Coastal Program (LCP) covering unincorporated coastal segments; (2) Very High Fire Hazard Severity Zones (VHFHSZ) designated by CAL FIRE and reviewed by the State Board of Forestry, which cover very large portions of the unincorporated back-country and drive defensible-space, ignition-resistant-construction, and access requirements; (3) FEMA Special Flood Hazard Areas (SFHA) along the San Diego River, San Dieguito River, San Luis Rey River, Otay River, Sweetwater River, Tijuana River, and associated coastal zones; and (4) Airport Land Use Compatibility Plans (ALUCP) administered by the San Diego County Regional Airport Authority's Airport Land Use Commission around MCAS Miramar (federal military), NAS North Island / Naval Outlying Landing Field Imperial Beach (federal military), Gillespie Field (Santee, county-owned), McClellan-Palomar (Carlsbad, county-owned), Brown Field (Otay Mesa, City of San Diego), Montgomery-Gibbs Executive (Kearny Mesa, City of San Diego), Ramona Airport (county-owned), Fallbrook Community Airpark (county-owned), Oceanside Municipal, and Jacumba Airport. Seismic-retrofit overlays are not a county-administered regime in San Diego (unlike parts of Los Angeles / San Francisco); California seismic building-code compliance applies statewide through the California Building Code adopted by the county.
- California Coastal Commission / County Local Coastal Program (LCP) — The county's LCP covers the unincorporated coastal segments near Del Mar Mesa, Torrey Pines extensions, Crest / Harmony Grove (tributary areas), and the Camp Pendleton / Oceanside boundary. An ADU within the coastal zone requires a Coastal Development Permit (CDP) unless categorically excluded; most single detached ADUs qualify for an Administrative CDP (noticed but ministerial-like) while those in sensitive-biological or visually-sensitive settings may require a heard CDP. The Coastal Commission retains appeal jurisdiction over county CDPs within the defined appeals area. State law (Gov. Code 65852.2(j)) preserves the CDP requirement for ADUs in the coastal zone notwithstanding the otherwise-ministerial state ADU framework.
- CAL FIRE / State Board of Forestry Very High Fire Hazard Severity Zones (VHFHSZ) and County Fire Code — Very large portions of unincorporated San Diego County — most of the East County back-country including Julian, Warner Springs, Descanso, Pine Valley, Jacumba, Campo, Boulevard, Dulzura, Potrero, Palomar Mountain, Cuyamaca, and the San Diego / Cleveland National Forest interface — are designated VHFHSZ in either the State Responsibility Area (SRA) or the county's Local Responsibility Area (LRA). An ADU in a VHFHSZ must comply with California Building Code Chapter 7A (WUI-rated exterior materials: ignition-resistant siding, dual-pane windows, 1/8-inch-max vent screens, Class A roofing, non-combustible eaves / soffits / decks), minimum 100-foot defensible-space per Pub. Res. Code 4291, minimum driveway width and turnaround per fire-district standards, and minimum fire-flow water supply (2,500 gpm residential standard, reduced for sprinklered ADUs per Sec. R313). CAL FIRE or the local FPD (Alpine, Bonita-Sunnyside, Deer Springs, Julian-Cuyamaca, Lakeside, North County, Pine Valley, Rancho Santa Fe, Rural FPD of San Diego County, Valley Center, etc.) reviews the ADU permit. The 2025 wildfire season reinforced these requirements; no county-wide moratorium has been imposed, but permit backlogs lengthen post-fire when affected areas surge rebuild applications.
- FEMA Special Flood Hazard Areas (SFHA) — National Flood Insurance Program — The county administers FEMA NFIP floodplain regulations for unincorporated parcels. Principal SFHA extents are along the San Luis Rey River (Bonsall, Pala, Pauma), San Dieguito River (Lakeside, Ramona uplands), San Diego River (Lakeside, Santee extensions), Sweetwater River (Spring Valley extensions), Otay River (Jamul, Dulzura, Otay Mesa extensions), and Tijuana River estuary (Tijuana / Imperial Beach extensions). ADUs in an SFHA require lowest-floor elevation to or above Base Flood Elevation plus 1 ft county freeboard, flood vents on enclosures below BFE, anchoring, and a post-construction Elevation Certificate. 2024-2025 saw several FEMA FIRM revision studies for Otay, San Luis Rey, and Sweetwater watersheds; owners should confirm current effective panel before design.
- Airport Land Use Compatibility Plans (ALUCP) — San Diego Regional Airport Authority ALUC — The San Diego County Regional Airport Authority serves as the ALUC for all airports in the county. ALUCP airport influence areas (AIAs) extend roughly 2-5 miles beyond each airport depending on runway configuration and establish safety zones (Zones 1-6) and noise contours (60/65/70 dB CNEL). Principal ALUCP overlays affecting unincorporated parcels are MCAS Miramar (extensive AIA covering Scripps Ranch fringes, Miramar Ranch North, Tierrasanta approaches, into unincorporated Rancho Santa Fe / Poway fringes), Gillespie Field (AIA extending into unincorporated Lakeside, El Cajon fringes, Bostonia), McClellan-Palomar (Carlsbad-adjacent unincorporated areas), Ramona Airport (large rural AIA), and Fallbrook Community Airpark (Bonsall / Fallbrook). An ADU in a safety zone may face density restrictions, CC&R / avigation-easement recording requirements, and noise-attenuation construction standards (STC-rated windows, forced-air HVAC with acoustic treatment). The ALUC reviews county-referred projects; in a safety-zone conflict the county may override only by a super-majority Board vote per PUC 21676.
- San Diego County Biological Mitigation Ordinance / Multiple Species Conservation Program (MSCP) — The county's MSCP covers south county unincorporated areas and establishes Pre-Approved Mitigation Areas and a Biological Mitigation Ordinance that triggers biological review for grading and construction in designated preserve-land overlays. An ADU outside the existing dwelling footprint that requires grading in a designated MSCP preserve or Biological Resource Core / Linkage area will trigger a biological review / mitigation obligation on top of the ministerial ADU permit. Inside a parcel's previously-disturbed building envelope the MSCP typically does not add requirements. The East County MSCP Subarea Plan remains pending final approval as of 2026-04-20.
County permitting (unincorporated parcels)
The County of San Diego Planning & Development Services (PDS) department is the single-point-of-contact for ADU permits on parcels in the unincorporated county. Unincorporated San Diego County covers approximately 3,570 square miles (about 79% of the county's 4,526 sqmi land area) and includes densely developed fringe areas (Ramona, Alpine, Lakeside, Spring Valley, Fallbrook, Valley Center), rural back-country (Julian, Warner Springs, Jacumba, Boulevard, Campo), and tribal lands (which are not county-permitted). The 18 incorporated cities (San Diego, Chula Vista, Oceanside, Escondido, Carlsbad, Vista, San Marcos, El Cajon, Santee, La Mesa, Encinitas, National City, Poway, Coronado, Imperial Beach, Lemon Grove, Del Mar, Solana Beach) permit their own ADUs independently. PDS combines planning / zoning review, building plan review, grading / drainage review, fire-district referral (most unincorporated areas are served by CAL FIRE / County Fire Authority or a local Fire Protection District rather than a city fire department), and environmental review (CEQA applicability is normally exempt for ministerial ADUs per Gov. Code 65852.2(f) and Pub. Res. Code 21080(b)(8)).
California state — ADU law and programs
State ADU law
California has the most aggressive statewide ADU preemption regime in the US, built from ~15 bills passed 2019-2025 and enforced by the Department of Housing and Community Development (HCD). The 2026 HCD ADU Handbook addendum (in effect with the 2025 Title 24 code cycle) is the operative state-level reference. The regime does four things at once: (1) preempts local zoning that would ban or unreasonably restrict ADUs; (2) imposes by-right ministerial approval with short statutory deadlines; (3) caps fees and utility-connection charges; and (4) empowers HCD to void non-compliant local ordinances.
State HOA preemption
California has the strongest statewide HOA-preemption regime in the US for accessory dwelling units, built from two bills: AB 670 (2019) voided ADU-prohibiting covenants on single-family residential lots, and AB 3182 (2020) extended and codified the preemption into the Davis-Stirling Common Interest Development Act (Civil Code §§ 4740 / 4741). The combination prohibits common-interest communities from banning ADUs, restricting rentals below 25% of separate interests, or treating ADUs as separate HOA interests. Limits remain: HOAs retain authority over reasonable design standards and statutory height limits, and the 2026 Carlsbad case (CalMatters coverage) established that an HOA's documented design-standards regime can effectively delay or constrain ADU approval short of outright prohibition.
State financing programs
California's flagship state-level ADU financing program — the CalHFA ADU Grant Program — is paused and has not been refunded since the original $100 million allocation was fully deployed 2023-12-28. The program provided up to $40,000 per qualifying homeowner for pre-construction and non-recurring closing costs and financed approximately 2,500 ADUs in two rounds. As of 2026-04, no new funding round has been announced in the state budget. CalHFA continues to publish anti-scam warnings because bad actors actively solicit homeowners claiming access to grant funds that no longer exist. State-level financing activity has shifted to local pilot programs (San Francisco, San Jose, Los Angeles, San Diego) and private financing products (Fannie Mae ADU mortgage, HELOC, construction-to-permanent).
State housing programs
California's state-level ADU programs are concentrated at HCD (technical guidance, ordinance review, enforcement) and the paused CalHFA grant pipeline (covered under stateFinancing). The state does not operate a central pre-approved ADU plan library — instead, AB 1332 (2024) created a preemption framework for local pre-approved plans with a 30-day ministerial-approval deadline, and major cities (Los Angeles, San Diego, San Jose, Sacramento, Berkeley) have rolled out their own plan catalogs. The California YIMBY coalition and other housing-policy organizations play an influential role in bill drafting; they are not state agencies but effectively drive much of the ADU legislative agenda. The Title 24 code cycle (now 2025, in effect for 2026 permits) is the authoritative building-code baseline.
Federal (United States) — ADU-relevant rules and programs
Federal ADU law
The United States has no federal statute that directly regulates accessory dwelling unit entitlement or design. Land-use authority over ADUs resides with states and local governments under the traditional police power. Federal engagement is limited to financing (Fannie/Freddie/FHA/VA/USDA), flood insurance (FEMA/NFIP), and discretionary housing programs (HUD), which are recorded in sibling sections of this file.
Federal financing programs
Federal housing-finance agencies and GSEs set nationwide underwriting rules that govern whether an ADU can be financed, appraised, and counted toward mortgage qualifying income. The relevant actors are Fannie Mae, Freddie Mac, FHA (HUD), VA, and USDA Rural Development.
Federal tax credits
There is no ADU-specific federal tax credit. ADUs may incidentally qualify for existing federal energy-efficiency and clean-energy tax credits when the ADU construction includes qualifying measures.
Federal housing programs
HUD administers several discretionary programs that can fund ADU-related activity at the grantee's election, but none is an ADU-specific program.
ZIP Code
- 92173
Post Office
- 440 W San Ysidro Blvd, 92173