ADU Pass
National City
San Diego County portion
Also in: No County
ADU Pass helps homeowners in National City, 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 allowed by-right ministerial under NCMC 18.30.380 + state preemption. National City's small-lot density (median lot under 5,000 sqft is common across the older Heritage Square / Old Town fabric), Naval Base San Diego AICUZ noise overlay along the I-5/Bay Marina corridor, and Sweetwater Authority will-serve discipline are the practical constraints rather than ordinance prohibitions.
Cost scenarios
| Scenario | Sq ft | Permit | Build | Total |
|---|---|---|---|---|
| minimum | 400 | $4,500 | $184,000 | $188,500 |
| 600 | 600 | $5,500 | $264,000 | $269,500 |
| midpoint | 675 | $6,000 | $297,000 | $303,000 |
| 1000 | 1,000 | $9,500 | $430,000 | $439,500 |
| maximum | 1,200 | $11,500 | $504,000 | $515,500 |
Fee breakdown (as of 2026-04)
Permitting process
Viability (permitted uses)
- Long-term rental: yes Long-term rental of an ADU is explicitly permitted under NCMC 18.30.380. AB 976 (effective 2025-01-01) precludes any owner-occupancy enforcement on detached ADUs. Strong long-term rental demand from Naval Base San Diego personnel + South Bay workforce.
- Short-term rental: with-restrictions National City regulates short-term rentals separately from ADU permitting; STR business license + Transient Occupancy Tax registration apply where STRs are permitted. Owners should confirm zone-specific STR permissibility before structuring around STR economics; ADU + STR pairing has historically been more constrained in National City than in surrounding North County coastal cities.
- Office rental: no ADUs are residential by definition under NCMC 18.30.380; office-only use to outside tenants would require rezoning. National City's commercial corridors (National City Blvd, Highland Ave, Plaza Blvd) carry the office-use zoning.
- Home office: yes Owner home occupation permitted under NCMC home-occupation provisions with restrictions on customer traffic, signage, and inventory storage.
- Studio / workshop: yes Personal artist studio / workshop use is consistent with residential occupancy; commercial sales activity pushes the use into the home-occupation category.
- Agriculture: no National City has no rural-residential or agricultural zones; the city is fully urbanized at high density.
- Relative support: yes Family occupancy of an ADU or JADU is explicitly permitted; JADUs require owner occupancy of one of the units (primary or JADU) per state law.
Incentives
Contacts
Utilities
- Water: Sweetwater Authority (joint powers between South Bay Irrigation District and City of National City; serves ~200,000 people in National City + Bonita + western/central Chula Vista; sources include Sweetwater Reservoir, Loveland Reservoir, and the National City Wells / Reynolds Desalination Facility) · 30d connect · $4,500
- Sewer: City of National City Public Works Sewer & Wastewater Division (city-operated collection: 97 miles of mostly 6- and 8-inch sanitary mains, 45 miles of closed storm collection, 4 pump stations); treated effluent processed at City of San Diego Metropolitan Wastewater Treatment Plant under the Metropolitan Wastewater JPA in which National City is a member agency · 30d connect · $5,500
- Electric: San Diego Gas & Electric (SDG&E) · 30d connect · $2,400
- Gas: San Diego Gas & Electric (SDG&E) · 21d connect · $1,800
Property values & taxes
Construction timeline
Realistic total: best 7mo · typical 11mo · worst 16mo
Modular pathway inspectors are occasional with modular
Financing
State ADU loans:
Insurance impact
National City's urbanized non-WUI status keeps admitted-market insurance broadly available for new ADU construction (unlike East County mountain communities). Premium delta is the conventional dwelling-coverage uplift for the new structure plus landlord-liability rider when renting. Coastal-frontage parcels along Bay Marina may face higher coastal/tidal exposure pricing.
HOA prevalence & preemption
National City has lower HOA prevalence than the master-planned coastal North County cities. Most single-family fabric (Old Town, Heritage Square, El Toyon, Lincoln Acres-adjacent) is fee-simple without active HOAs. Newer Granger / Paradise Hills-adjacent subdivisions and condo conversions have CC&Rs but California's AB 670 / AB 3182 (Civil Code Sections 4740 / 4741) preempts HOA bans on ADUs.
Regulatory overlays (4)
- coastal-commission
Only the narrow Bay Marina / 24th Street tideland frontage is in the California Coastal Zone. Nearly all residential parcels are inland of the Coastal Zone boundary and exempt from CDP processing. The handful of bay-frontage parcels require LCP review through the City and CCC concurrence. - airport-noise-zone
Naval Base San Diego AICUZ (Air Installation Compatible Use Zone) noise overlay covers the Bay Marina / I-5 corridor parcels with APZ-2 and Noise Zone 2 disclosures and acoustical mitigation requirements (interior STC 45) for new dwelling units. Does not prohibit residential use but adds envelope cost for fenestration upgrades on affected parcels. - seismic-retrofit-zone
Seismic Design Category D per ASCE 7 (Rose Canyon Fault Zone is the regional dominant). New ADUs designed under CRC seismic provisions; soft-story retrofit is occasionally relevant for ADUs over street-level garages on older Heritage Square / Old Town parcels. - wetland-overlay
Sweetwater River corridor (the river forms the south boundary of the city) and Paradise Marsh / Paradise Hills riparian areas trigger riparian setbacks per City zoning and possible USACE Section 404 jurisdiction for parcels close to the channel.
Technical envelope (climate & building code)
Climate & energy code
Building code
Amendments:
- Amendment
- Amendment
- Amendment
Legal history (timeline)
Current ordinance: National City Municipal Code Section 18.30.380 (ADU) and 18.30.390 (JADU), adopted 2017-01-01, last amended 2024-01-01
- 1887-09-17 — Incorporation of National City (city-ordinance)
National City incorporated as a general-law municipality, the second-oldest incorporated city in San Diego County (after the City of San Diego itself).
Effect: Established home-rule planning authority that the City has used since to administer its zoning and building codes; NCMC Title 18 (Land Use Code) is the modern descendant. - 2017-01-01 — California SB 1069 / AB 2299 first-generation statewide ADU streamlining (state-law)
Initial statewide preemption of local ADU bans, ministerial approval requirement, prohibition on most parking mandates near transit.
Effect: Triggered National City's first conforming ADU ordinance update; established the framework that NCMC 18.30.380/390 layered onto. - 2020-01-01 — California AB 68 / AB 881 / SB 13 / AB 670 second-generation ADU package (state-law)
Required ministerial 60-day approval; SB 13 waived impact fees under 750 sqft and required proportional fees above; AB 670 voided HOA ADU bans on single-family lots.
Effect: National City reorganized its ADU regulations into NCMC 18.30.380 (ADU) and 18.30.390 (JADU) to conform; SB 13 fee waiver materially improved economics for the city's predominantly small-lot infill ADU pipeline. - 2025-01-01 — California AB 976 owner-occupancy permanent prohibition + SB 1211 parking-replacement waiver (state-law)
AB 976 permanently prohibits owner-occupancy enforcement on detached ADUs; SB 1211 prohibits requiring replacement parking when a garage/carport is demolished or converted for an ADU.
Effect: Removes parking-replacement as a gating constraint on garage-conversion ADUs in National City's narrow-lot Heritage Square / Old Town neighborhoods where on-site replacement parking was historically infeasible. - 2025-12-05 — HCD ordinance technical assistance letter to National City (state-law)
California HCD issued a technical-assistance review of National City's ADU ordinance under Government Code Section 65852.2.
Effect: Identified specific NCMC 18.30.380 provisions HCD believes do not conform with current state law; a National City conforming ordinance update is on the Planning Commission / Council calendar for 2026.
Known issues (4)
- policy-review — HCD's 2025-12-05 ordinance technical assistance letter flagged non-conforming provisions in NCMC 18.30.380. National City staff has acknowledged a 2026 conforming ordinance update is needed; the underlying state preemption is in force regardless of when the local text is amended.
- other — Naval Base San Diego AICUZ noise overlay covers the I-5 / Bay Marina corridor and adds acoustical-mitigation cost (~$3,000-$8,000 in fenestration / wall-assembly upgrades) for ADUs in affected zones. Disclosure burdens transfer to future tenants and resale buyers.
- other — Sweetwater Authority will-serve discipline can delay water meter sets for new ADUs in capacity-constrained sub-zones; verify well in advance of submittal. Connection fees and capacity charges also apply at and above 750 sqft.
- other — Median single-family lot size in National City's older Heritage Square / Old Town fabric is under 5,000 sqft; the 4-ft side/rear setbacks plus existing primary dwelling often leave only enough envelope for a 600-800 sqft detached ADU even though the ordinance allows 1,200 sqft.
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
- 91950
Post Office
- 710 E 16th St, 91950