National City ADU Regulations & Zoning
National City, California
Zip Codes: 91902, 91950, 91951, 92136
Neighborhoods: Alta Vista, Paradise Hills, South Bay Terraces, Lincoln Acres
Our quick take on National City: ADU-Friendly
National City allows up to a 1200 sqft ADU with four foot side and rear setbacks, and no minimum lot sizes. You can build a single story structure, or an ADU over a garage. National City does require soils reports (>500 sqft), which adds some processing time and expense
National City Regulation & Permitting Requirements:
ADU SIZE & BUILDING CONSTRAINTS
What size detached ADU can you build in National City?
National City allows for up to a 1200 sqft detached ADU. An ADU constructed within the footprint of an existing dwelling or a detached structure shall not be subject to a maximum square footage of total floor area (so you could convert a large barn, for example, of any size).
What is the height requirement for an ADU in National City?
Per the National City ADU code, attached or detached ADUs shall not exceed the height of the primary dwelling or 16 feet, whichever is greater. For an ADU constructed above a garage or on a lot smaller than 5,000 square feet, the height shall not exceed 25 feet. On a property with a multi-family residential structure, the height of a detached ADU shall not exceed 16 feet.
Can you build a 2-story ADU in National City?
Yes, you may build a 2-story ADU if you provide parking on the ground floor of the ADU, in which case the maximum height shall be the same as the primary dwelling in the underlying zone. In other words, you can build an ADU over a garage.
How big can an attached ADU be in National City?
The square footage of any attached ADU may not to exceed 50% of the primary dwelling square footage, or 1,200 sqft, whichever is less, but not less than 800 square feet.
What are the design requirements for ADUs in National City?
All ADUs are required to be compatible with the primary unit. This typically means compatible in terms of design, building and roofing materials, colors, and exterior finishes.
SETBACKS
What is the setback requirement for an ADU in National City?
For all ADUs, the front setback shall be a minimum of 15 feet, the exterior and interior side yard setback shall be a minimum of 4 feet, and the rear yard setback shall be a minimum of 4 feet.
No setback shall be required for an existing living area or permitted accessory structure or a structure constructed in the same location and to the same dimensions as an existing structure that is converted to an accessory dwelling unit or to a portion of an accessory dwelling unit.
What is the minimum distance the ADU must be from existing structures?
The minimum required distance between structures is 5 feet in National City.
ADDITIONAL REQUIREMENTS
Does National City require in-person submission of plans for an ADU?
No, National City allows digital submission of applications for an ADU.
Does National City require a soils report for an ADU?
Yes, National City requires a soils report for ADUs of 500sqft or more.
Does National City require coastal development permits?
National City does not have any residentially zoned properties within the coastal zone.
MULTIFAMILY
How many ADUs does National City allow for multifamily properties?
Two detached ADUs are permitted on lots with an existing multi-family residential dwelling. Note that the building itself is what will qualify, not just the underlying zoning — so you could likely just build one ADUs on a multifamily zoned property that currently has a single family home on it.
Additionally, you can convert existing non-livable space within an ADU up to 25% of the existing dwelling units.
Can you stack detached ADUs on top of each other?
No, because an ADU cannot stand higher than 16′ on multifamily properties.
Can you attach two ADUs to each other in National City?
Yes, if the lot has an existing multi-family residential structure you can propose to construct up to two detached ADUs in an attached configuration as long as it meets all underlying zoning, life safety, and building code requirements.
Can you convert existing space to an ADU?
Yes, existing non-livable space may be converted to ADUs (e.g. storage areas and garages). There is no limit on the number of ADUs that can be created in this manner. These conversions are in addition to the allowed number of detached ADUs.
All information verified with a planner for National City in November 2022.
PARKING
What is the parking requirement for an ADU in National City?
No additional parking is required for an ADU. If an ADU is constructed within existing garage or covered parking, then no replacement parking spaces may be required.
Where can a parking space be located?
If a parking space is required, it may be located within the setbacks and in an existing driveway as tandem parking. Parking spaces don’t need to be replaced when a garage, carport, or covered parking structure is demolished in conjunction with the construction of an ADU or converted to an ADU.
LANDSCAPING
What are the landscaping requirements for an ADU in National City?
One twenty-four-inch box tree shall be planted within the required fifteen foot front yard setback for ADUs or in the abutting parkway. Existing trees that are at least fifteen feet high and fifteen feet in width may be used to satisfy this requirement.
