Multifamily and Duplex Properties for Sale in National City: Zoning and Rent Rules

By Matthew Martinez, Founder, CEO & Managing Broker, Diamond Real Estate Group. California DRE #01869679.

National City zones more land for apartments than most South Bay cities. Its residential code has four multifamily tiers, from about 15 units per acre in RS-3 to roughly 75 in RM-3, plus mixed-use corridors at the same top density. The Attorney General’s chart lists no local rent limit for National City, so AB 1482 sets the rent cap.

What multifamily in National City looks like

Rental stock ranges from small-lot attached homes and courtyard buildings to mid-rise apartments near downtown and the trolley lines. The zoning map shows the full residential range: RS-1 and RS-2 single-family, RS-3 medium-low density multi-unit, RM-1 through RM-3, mixed-use districts that allow housing, and a Mobile Home Park overlay (National City zoning map). West of I-5, the Westside Specific Plan sets its own housing zones.

Two-to-four-unit buildings can use 2-4 unit financing. Larger RM-2 and RM-3 buildings are apartment loan territory.

Where the zoning allows it

Sources: NCMC Ch. 18.21, Ch. 18.24, zoning map.

All four residential tiers permit multiple-unit and single-attached dwellings on a minimum 5,000 sq ft lot, with lot coverage capped at 75% (NCMC § 18.21.020–.040). A mixed-use project that is mostly residential must still include at least 10% commercial floor area (Ch. 18.24). The code’s objective design standards (Ch. 18.49) apply to new multifamily, which helps make approval more predictable.

ADUs and SB 9. ADU rules are in NCMC § 18.30.380 (zoning overview). SB 9 applies on qualifying RS-1 and RS-2 single-family lots. See our SB 9 guide and ADU investment guide.

Rent rules: state law only

The Attorney General’s rent cap chart lists no local rent limit for National City. For the San Diego area, AB 1482 allows increases of up to 8.8% from August 2025 to July 2026 and 8.2% from August 1, 2026 to July 31, 2027 (AG rent caps). Exempt from the cap: buildings with a certificate of occupancy from the last 15 years, most single-family homes not owned by corporations or REITs, and owner-occupied duplexes. After a tenant has lived in a unit 12 months, an eviction needs an at-fault or no-fault just cause (AG). See AB 1482 for landlords and just cause eviction. Before you close, confirm with the city clerk that no new local ordinance has been adopted.

National City rental property rules

• Mobile Home Park overlay. The zoning map designates an MHP overlay. Mobile home park spaces fall under state Mobilehome Residency Law, and AB 1482 does not cover mobilehomes unless the park owner rents them out (AG).
• Coastal and Port land. The Coastal Zone overlay and Port jurisdiction on the bayfront limit new residential there (zoning map).
• Lincoln Acres. This unincorporated pocket follows County of San Diego zoning, not the city’s table above.
• I found no rental registration or inspection program on official city pages. Confirm with the city.

Freeway, industry and older building stock

Some National City housing sits near freeways or next to industrial zones. Industrial buildings must set back 20 ft from a residential zone and step down in height within 100 ft (NCMC Ch. 18.25). Still, check truck routes and air quality before planning a redevelopment. Many apartment buildings date from the 1950s to 1980s, so look at soft-story parking (seismic retrofit guide). Buildings with three or more units and elevated balconies need SB 721 inspections (SB 721).

Underwriting a National City multifamily purchase

1. Confirm whether the parcel is under the base code, the Downtown or Westside plan, or county rules.
2. Divide the lot area by the zone’s per-unit figure (2,900, 1,900, 900 or 580 sq ft) to check legal density and room for more units.
3. Confirm the certificate-of-occupancy date for AB 1482, and use the 8.2% cap for increases after August 2026.
4. Get estoppels and rent rolls (estoppel certificates).
5. Inspect balconies, stairs and soft-story conditions.
6. For an RM-2 or RM-3 redevelopment, model the 65 ft or 95 ft height and 75% coverage (rental property analysis).

Questions people ask

Sources & notes

1. City of National City zoning map
2. NCMC Ch. 18.21 residential zones
3. NCMC Ch. 18.24 mixed-use zones
4. NCMC Ch. 18.25 industrial zones
5. National City zoning overview
6. California Attorney General: rent caps
7. California Attorney General: landlord-tenant issues

General information, not legal or tax advice. Last reviewed October 2026 by Matthew Martinez.

Related: National City real estate guide · Commercial real estate in National City · Multifamily investing guide · Investor services