IL Total Design and Build
Escondido
- Active license
- Bond on file
- Insured
- 7 yrs licensed
ADU builders and rules in National City
National City ADU rules sit in two sections of its zoning code, but the state housing department warned in December 2025 that the city's ordinance, last updated in 2021, may be out of date. Here's what we could confirm about building an ADU in National City, and who to call.
National City ADU facts
- ADU code
- NCMC 18.30.380 (junior ADUs: 18.30.390)
- Ordinance on file with HCD
- 2021, flagged as possibly outdated
- Junior ADU size
- 150 to 500 sq ft, inside the house
- High school fee
- $3.01/sq ft (Sweetwater Union)
- How to apply
- Email or Building Division counter
Verified ADU builders serving National City
All San Diego County buildersNone of our verified builders is based in National City yet; these work across San Diego County. Each holds an active B license with a bond on file, checked with the state on Oct 26, 2026.
Adama Builders
San Diego
- Active license
- Bond on file
- Comp exempt
- New license
Snap ADU
San Diego
- Active license
- Bond on file
- Insured
- 5 yrs licensed
GW Construction
San Diego
- Active license
- Bond on file
- Insured
- 2 yrs licensed
EG Construction
Chula Vista
- Active license
- Bond on file
- Comp exempt
- 21 yrs licensed
Eco Home Builders Inc
San Diego
- Active license
- Bond on file
- Insured
- 5 yrs licensed
National City ADU rules
National City's ADU rules are in its municipal code: section 18.30.380 covers accessory dwelling units and 18.30.390 covers junior ADUs. The city's ADU page describes an ADU as an attached or detached unit with independent living space on a residential lot, and a junior ADU as a unit of 150 to 500 sq ft inside an existing or proposed single-family home.
According to the planning FAQs, ADUs are generally allowed in most single-family residential zones, and planning counter staff can check your parcel's zoning first. We couldn't read the code text itself, so we don't list National City's local size, height or setback numbers here. The statewide minimums are in our guide to California ADU laws, and our junior ADU guide explains the smaller unit.
Is National City's ADU ordinance up to date?
Maybe not. On December 5, 2025 the state housing department sent National City a letter of technical assistance saying the most recent ADU ordinance it had on file for the city was from 2021 and, given many changes to state ADU law since, may be out of compliance. HCD asked the city to respond by January 4, 2026, either explaining how the ordinance still complies or giving a plan to repeal or amend it. The letter also notes that an ADU ordinance that doesn't meet state law is null and void, and the city must apply state standards instead.
Ask which rules apply before you design. We couldn't confirm whether National City has amended or repealed its ADU ordinance since HCD's letter. Ask the Planning Division whether the 2021 standards or state ADU law apply to your lot.
National City ADU fees
| Fee | What applies |
|---|---|
| City impact fees | Under state law, none on an ADU of 750 sq ft or less; above that, proportional to the main house |
| High school fee (Sweetwater Union) | $3.01 per sq ft for grades 7–12 residential additions and conversions, from June 22, 2026 |
| Permit and plan check fees | Not published on the city's ADU page; the Building Division quotes them |
An elementary school district fee may also apply; ask which district serves your address. For what the build itself costs, see what an ADU costs in San Diego or try the ADU cost calculator. Paying for it is covered in our ADU financing guide.
Getting a National City ADU permit
The city's ADU page says you can email your application packet to building@nationalcityca.gov or bring it to the Building Division counter at City Hall, 7:00 a.m. to 4:30 p.m., Monday through Thursday. General ADU questions go to the Planning Division at 619-336-4310; permit and fee questions go to the Building Division at 619-336-4210. The page also lists an ADU Loan Program; ask the city whether it is taking applications.
The National City Fire Department recommends a pre-development meeting for ADU projects before you submit. Once your application is complete, state law gives the city 60 days to approve or deny it.
Before you hire, read how to hire an ADU contractor and check a contractor's license. You can also compare verified ADU builders in San Diego County.
Common questions
Can I build an ADU in National City?
Generally yes. National City's planning FAQs say ADUs are allowed in most single-family residential zones; check your parcel's zoning with the Planning Division at 619-336-4310.
Where are the National City ADU rules?
In the National City Municipal Code: section 18.30.380 for ADUs and 18.30.390 for junior ADUs. HCD warned in December 2025 that the city's 2021 ordinance may be out of date, so confirm which standards apply.
How do I apply for a National City ADU permit?
Email your application packet to building@nationalcityca.gov or bring it to the Building Division counter at City Hall, open 7:00 a.m. to 4:30 p.m. Monday through Thursday.
What are National City ADU fees?
State law bars impact fees on ADUs of 750 sq ft or less. Sweetwater Union High School District charges $3.01 per sq ft, and the Building Division quotes permit and plan check fees.
Sources
- City of National City Planning DivisionAccessory Dwelling Units (ADUs)
- MunicodeNational City Municipal Code, Title 18 (Zoning)
- California Department of Housing and Community DevelopmentNational City ADU ordinance updates, letter of technical assistance (December 5, 2025)
- City of National CityPlanning FAQs
- National City Fire DepartmentGet plan reviews and permits
- Sweetwater Union High School DistrictDeveloper Fees
- California Legislative InformationGovernment Code § 66311.5 (fees)
- California Legislative InformationGovernment Code § 66317 (permit timelines)
General information, updated Oct 26, 2026. Rules and fees change; confirm with the National City permit office before you rely on them.