National City Homes with ADU, Casita & Guest House

Welcome to your hub for Accessory Dwelling Units (ADUs) in National City, CA. This guide connects you to live MLS listings, verified local ADU rules, and small-lot zoning opportunities in one of South Bay’s most centrally located cities.

With strong renter demand, freeway and trolley access, and state-backed ADU protections, National City is well-positioned for multi-gen living, second-unit rental income, and long-term wealth building through additional units.

Fun Fact: National City is the second-oldest city in San Diego County and is known for its famous Mile of Cars auto district and bayfront access just south of downtown San Diego.

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⭐ Local ADU Expertise — Jessica Rinaldi: Jessica reviews National City’s ADU Handbook and municipal code to flag lots with strong ADU feasibility, including small-lot opportunities, 4-foot rear/side setbacks, transit-adjacent parcels with parking exemptions, and garage conversion potential near major corridors and the trolley. She helps buyers and owners underwrite rental projections, build costs, and permitting risk specifically for National City.

Should You Build or Buy an ADU in National City?

ADUs in National City must be allowed at least 800 sq ft under state standards. California law guarantees up to 800 sq ft for qualifying ADUs even when local lot standards are tight, while the city’s own ordinance and ADU Handbook provide pathways for larger floor areas when code conditions are met.
National City’s rental demand supports second-unit income. As a dense South Bay city near naval facilities, freeways, and the trolley, well-located ADUs can serve long-term renters, multi-gen families, and workforce tenants.
State law locks in reduced ADU setbacks and ministerial approvals. Detached ADUs can use 4-foot rear and interior side setbacks, and qualifying projects are processed ministerially when they meet state and local standards.
Parking rules favor transit-oriented ADUs in National City. ADUs within a half-mile of public transit and many garage conversions qualify for no additional parking requirement, and replacement parking is not required when a garage or carport is converted to an ADU.

Where Can You Find ADU, Casita & Guest House Listings in National City?

Live MLS feed — updated throughout the day with National City homes that include a guest house or second unit:

New National City ADU-capable and guest house listings appear regularly — check back often.

Where Is National City, CA Located?

National City sits just south of downtown San Diego along San Diego Bay, bordered by San Diego and Chula Vista, with quick access to I-5, I-805, and SR-54 — and only minutes from the U.S.–Mexico border.

National City ADU & Financing Frequently Asked Questions

Q: How big can a detached ADU be in National City?

A: Detached ADUs in National City must be allowed at least 800 sq ft under California’s state standards, with local regulations and the city’s ADU Handbook outlining when larger units may be approved based on height, design, and fire-access requirements.

Q: Can I build multiple ADUs on a multifamily property in National City?

A: Yes — like other California cities, National City must allow detached ADUs plus interior conversion ADUs on eligible multifamily lots, subject to building code and safety standards under state law.

Q: Is owner-occupancy required for my ADU in National City?

A: No. Under California’s AB 976 (effective January 1, 2024), cities and counties are prohibited from imposing owner-occupancy requirements on ADUs, so your ADU can be rented even if you do not live on site, as long as other laws are followed.

Q: What are the best ways to finance an ADU in National City?

A: Most ADU projects are funded using a cash-out refinance, a second mortgage or HELOC, or a purchase loan structured around future rental income. Solid ADU documentation and permits help support appraisals and lender underwriting.

How Can Solve Realty Help You Plan an ADU in National City?

Solve Lending & Realty helps National City homeowners and investors evaluate zoning, setbacks, parking exemptions, and ADU income potential before you build or buy.

Jessica Rinaldi provides end-to-end support — from reviewing the city’s ADU Handbook and site conditions to crafting offers and connecting you with the right loan structure.