ADUs in National City, CA
✓ Verified November 1, 2026 Rules, fees, and timelines below were verified November 1, 2026. Anything marked “confirm” or “to verify” is still open.
The full text of Municipal Code §§18.30.380 (ADUs) and 18.30.390 (JADUs) was not readable in this pass, so the size, height, setback, and parking figures below rest on two builder guides citing the code and are labeled as such throughout. Confirm them against the code text before designing. The city's ordinance identity, application routes, contacts, AB 1033 status, and multifamily counts below are city-published.
Lands in an adopted specific plan (Westside, Harbor District) are governed by that plan's regulations where they differ from Title 18 — check specific-plan status per parcel, not just zoning.
The City has its own ADU ordinance (Municipal Code §§18.30.380 and 18.30.390; zoning title re-adopted by Ordinance No. 2024-2529, April 2, 2024). Planning (619) 336-4310; Building (619) 336-4210, building@nationalcityca.gov.
Does it apply to my lot? — address check
Enter a San Diego County street address. The checker geocodes it and checks public transit stops nearby. Privacy: your typed address goes directly from your browser to OpenStreetMap's free Nominatim geocoder and the public SanGIS transit-stops layer. It never touches an ADUKey server — ADUKey has no server endpoint for this, so there is nothing to send it to.
Parking-exemption rule: no parking required within a 1/2-mile walking distance of public transit (bus stops included). Straight-line distance is measured first: a straight-line miss is definitive, a straight-line hit is provisional until the walking route is checked.
What you can build
| Rule | What applies | Note |
|---|---|---|
| Detached ADU size | Up to 1,200 sq ft; an ADU within the footprint of an existing dwelling or detached structure is not subject to a maximum size (SnapADU) | Builder guides citing the code — code text not read; confirm. |
| Attached ADU size | The lesser of 50% of the primary dwelling or 1,200 sq ft, but not less than 800 sq ft | Builder guides citing the code — code text not read; confirm. |
| Height | Primary dwelling's height or 16 ft, whichever is greater; above a garage or on a lot under 5,000 sq ft: up to 25 ft; multifamily detached: 16 ft; 18 ft near major transit/high-quality corridor on the 4-ft track, +2 ft to match roof pitch | Builder guides citing the code and state law — confirm. |
| Setbacks and separation | Front 15 ft; side and rear 4 ft; no setback for conversions or same-location/same-dimension rebuilds; 5 ft building separation | Builder guides citing the code — confirm. |
| Design | Compatible with the primary unit (design, materials, colors, finishes); one 24-inch box tree within the 15-ft front setback or abutting parkway (existing trees ≥15 ft may satisfy it) | Builder guides only. |
| Junior ADU (JADU) | 150–500 sq ft, within an existing or proposed single-family dwelling; owner-occupancy required in either the main home or the JADU (builder guide); no owner-occupancy for standard ADUs (state law) | Size definition is city-published; owner-occupancy is a builder guide. |
| Parking | No additional parking required for an ADU (builder guides); no replacement parking when parking is demolished/converted for an ADU | “No additional parking at all” is builder-guide consensus, not city-code text read. The no-replacement rule is safe regardless (state law + council report). |
| Minimum rental term | Longer than 30 days (state law); the city's 2025 short-term-rental ordinance excludes ADUs permitted under §18.30.380 and JADUs under §18.30.390 | The STR ordinance itself is not an ADU rule — it excludes ADUs from its definition, consistent with the state rule. |
| Impact fees | Exempt for ADUs 750 sq ft or smaller (state law, confirmed locally); the city raised development impact fees in 2026 — ADU amounts to confirm. From Jan 1, 2027 (SB 1117, builder guide), fees on ADUs over 750 sq ft are calculated only on livable space above 750 sq ft | ADU-specific amounts after the 2026 increase were not extracted; SB 1117 is builder-guide context, not a city statement. |
| Permit fees | Not published — confirm with the Building Division, (619) 336-4210 | City FY 2026–27 Master Fee Schedule exists (adopted April 21, 2026, eff. July 1, 2026) but ADU totals were not extracted; builder $10–$12/sq ft estimates are not city fees and are not published here. |
| Multifamily lots | At least 2 detached ADUs, up to the number of existing units, max 8 (SB 1211 raised the cap from 2); conversions of non-habitable space up to 25% of units (minimum 1) | Counts and no-replacement rule are city-published (Oct 2025 council report); stacking/attached-configuration details are builder guide. “No SB 1211 projects submitted” is dated Oct 2025. |
| Overlays to check | Coastal (see section below); no mapped Fire Hazard Severity Zone per CAL FIRE 2025 LRA summary (not “no fire risk”); FEMA zones A/AE/AH/AO/VE touch parts of the city; Westside/Harbor District specific plans may carry their own standards | Fire and flood figures are third-party summaries of CAL FIRE/FEMA data, not city rules — per-parcel checks required. Hillside ADU rules: to verify. Historic-district status for ADU purposes was not researched. |
Permit path
- Confirm jurisdiction, coastal status, and specific-plan status with the Planning Division ((619) 336-4310).
- Submit. Complete packets, including a Credit Card Authorization Form, may be emailed to building@nationalcityca.gov or dropped off in person at the Building Division Counter at City Hall, 7:00 a.m.–4:30 p.m., Monday–Thursday. No portal name was found — do not assume one.
- Decision. Ministerial decision within 60 days of a complete application (state law).
Builder guides estimate 3–4 months for single-family permits and 4–6 months for multifamily/complex projects, with each review round ≤30 business days — label those as builder estimates. A soils/geotechnical report for ADUs 500 sq ft or larger is reported by one builder guide only — flag it, do not treat it as a city rule. City Hall street address was not stated on the ADU page text read — confirm before publishing one.
Pre-approved plans — none verified
No pre-approved plan program was verified in current city sources. The current city ADU page lists an ADU Handbook, regulations, permit applications, and an ADU Loan Program marked “Coming Soon” — no pre-approved plans, and neither builder guide mentions one. An older third-party page (~2024) referenced pre-approved plans as a city-page link label, but that link could not be confirmed on the current page. Publishable line: no pre-approved plan program verified — to confirm, not “the city offers none.”
Coastal zone — a split jurisdiction
National City has a certified Local Coastal Program (Land Use Plan certified July 10, 1997; Balanced Plan LCP amendment certified February 6, 2025). But most bayfront land is not under city CDP authority: in the ~77-acre Balanced Plan area, only a small inland portion of the bayfront is under the city's coastal permit authority — the waterfront is under the jurisdiction of the Port of San Diego and the U.S. military. Builder guides agree: the city processes CDPs on city coastal parcels; most bayfront tidelands (Marina District, etc.) are under Port jurisdiction; city coastal approvals in appealable areas may be appealed to the Coastal Commission. ADU-specific CDP waiver criteria, fees, and timelines were not verified from a city or Commission source. Confirm your parcel's status and permit authority with the Planning Division before designing.
Separate sale (AB 1033)
Not adopted as of October 2025, per the city's own council report, with a March 2026 builder guide in agreement. Confirm, this changes fast. The County's AB 1033 adoption applies to unincorporated areas only, not the City of National City.
Recent ADU activity — fiscal year, not calendar year
These are fiscal-year figures, not calendar-2025 figures, and must not be relabeled: July 1, 2024–June 30, 2025 — 35 ADUs completed, 40 ADU permits issued (of 194 total units completed and 110 total permits issued), per the city's October 21, 2025 council report. The calendar-2025 count (city 2025 Housing Element APR, HCD Table A2) was not retrieved — to verify.
What it costs (county range, not National City data)
Cost band $300,000–$450,000+ is a San Diego County range, not verified National City data. Use the calculator below with your own numbers. One builder guide cites ~$375–$600/sq ft construction — not National City data, and not used as a default.
Rent calculator
Defaults below are EXAMPLES — editable placeholders, not verified local rent or cost data. Type your own numbers.
Verified builders in San Diego County
One metro-level profile per builder, linked from every city page they serve. Profiles are never duplicated per city, so a correction lands everywhere at once.
Frequently asked questions
Do I need parking for an ADU in National City?
No additional parking is required for an ADU, per both builder guides — but that rule was not confirmed in city-code text read, so it is labeled builder-guide consensus on this page. What is safe regardless: no replacement parking when a garage, carport, or covered parking is demolished or converted for an ADU (state law, SB 1211, confirmed in the city's October 2025 council report).
Do I need a coastal permit for an ADU in National City?
Most homes in National City are outside the Coastal Zone. If your parcel is in the bayfront coastal area, expect a Coastal Development Permit: from the City on city coastal parcels, or from the Port of San Diego on bayfront tidelands. Confirm your parcel's status and permit authority with the Planning Division before designing. No coastal boundary, fee, or timeline is published here.
How big can an ADU be in National City?
Per builder guides citing the code (not code text read): detached up to 1,200 sq ft; attached the lesser of 50% of the primary dwelling or 1,200 sq ft, but not less than 800 sq ft. Height: the primary dwelling's height or 16 ft, whichever is greater (25 ft above a garage or on a lot under 5,000 sq ft). State law separately guarantees 800 sq ft / 16 ft.
Can I sell an ADU separately from the house in National City?
No. The city's own October 21, 2025 council report states no AB 1033 separate-sale ordinance had been contemplated or adopted as of then, and a March 2026 builder guide agrees. Confirm, this changes fast. JADUs can never be sold separately even where AB 1033 is adopted.
Sources
- City of National City ADU page (city-published)
- City of National City council agenda report, October 21, 2025 (city-published; AB 1033, SB 1211, fiscal-year ADU figures)
- City of National City FY 2026–27 Master Fee Schedule (city-published)
- City of National City short-term-rental ordinance, Ord. No. 2025-2544 (city-published)
- Coastal Commission staff report, LCP amendment (jurisdiction split)
- National City ADU regulations — SnapADU (builder guide)
- National City ADU regulations — Better Place (builder guide, March 2026)
Not legal advice. This page is a starting point, not a parcel approval. Confirm your lot with the city before you build, buy, or sign anything.
Report an outdated rule
Rules change. If something on this page no longer matches the city's current rules, tell us what changed and where you saw it. Reporting is not wired to a destination yet — your note stays on this page and is not sent anywhere.