ADU permit process

Meeting ADU Height Requirements in San Diego: Navigating Zoning Laws

Constructing an accessory dwelling unit (ADU) can be a great way to add living space to your property in San Diego. However, with ADU development on the rise, the city has implemented zoning regulations to control their size and height. Before building your ADU, it’s important to understand San Diego’s height limitations to ensure your project follows the rules. San Diego ADU Contractor prevents permitting delays and citations down the road.

Why Height Matters

ADU height restrictions aim to maintain neighborhood aesthetics and prevent units that are disproportionately large compared to surrounding homes. Excessively tall ADUs can feel out of place and create privacy or shading issues on adjacent properties. That said, some height allowances are necessary to make ADUs practical to live in. Finding the sweet spot between these priorities is the goal of San Diego’s regulations.

Height Limits for Detached ADUs

Detached ADUs (those in a separate structure from the main house) must comply with the following height allowances:

  • 16 feet maximum height if located 4 feet or more from the property line
  • 14 feet maximum height if located less than 4 feet from the property line

These limits are quite restrictive. While they help minimize impacts to neighbors, constructing a detached ADU with usable interior height and appropriate roof pitch will require careful planning.

Strategies like excavating the footprints, using below-grade space, or incorporating varied roof lines can help maximize height within the limits. Removing and rebuilding non-compliant existing structures may be another option. Professional architects experienced in San Diego ADU design can tailor creative solutions to make the most of the 14-16 foot building envelope.

Allowances for Attached ADUs

Attached ADUs connect directly to the main house, such as a basement conversion or addition. Their height follows the limits already permitted for the existing home rather than the reduced heights for detached units. For example, if your home complies with a 30 foot height limit under its zoning, an attached ADU can also reach 30 feet.

Measuring ADU Height

San Diego determines ADU height as the vertical distance from the existing grade to the uppermost roofline directly above that grade. Grade refers to the ground elevation around the perimeter of the structure.

On sloped sites, the “average” existing grade around the full ADU is used to measure to the highest point of the roof. You can’t pick the lowest point on the slope to get a higher allowable overall height.

Roof equipment like solar panels, chimneys, and vents aren’t included in the height measurement if they don’t increase the roof elevation by over two feet. If they do exceed two feet, however, the city counts the new elevation.

Seeking Variances for Additional Height

In special cases where meeting the height limits would create practical difficulties or extreme constraints, it may be possible to apply for a zoning variance. This is a discretionary approval that allows an exception to the rules.

However, variances can be challenging to obtain. You must prove that adhering to the regulations would pose an unreasonable hardship, making it difficult to gain approval.

They can also advise whether your property may qualify for pre-approved height allowances above 16 feet, such as in the Coastal Overlay Zone or with community plan exemptions.

Working Within the Limits

San Diego’s ADU height limits reflect larger concerns over neighborhood fits and privacy impacts. While they pose design challenges, most projects can creatively comply with 14-16 foot restrictions for detached units or existing home allowances for attached units.

With careful planning from an experienced architect, your ADU can maximize height within the rules. And if building up to 16 feet simply won’t work, attached designs or variance requests remain possibilities. Though more restrictive than other cities, San Diego’s height limits ensure ADUs meet community goals—even if they require some extra design creativity to make livable interiors.