The San Diego Bonus ADU program has many flaws but of chief concern for urban wildfire safety are those aspects that allow dense construction in the urban wildland interface without consideration for safe evacuation.
The regulation modifications related to urban wildfire safety are listed and annotated below. City Council will be doing a second reading in two weeks before the regulations are officially adopted. For a full read out of the changes, visit 2025 SD Bonus ADU Revisions – Adopted | NFABSD.
ADUs will be capped at 6 ADUs/JADUs on single-family lots of 10,001 sf or greater whether or not the location is inside the Sustainable Development Area one mile walking distance to transit. For smaller lots the number decreases to 4 or 5. Most lot sizes in fire prone areas are under 8000 sf and would have a maximum of 4 ADU/JADU allowed.
Additionally, steep slopes will not be included in the lot size for calculating allowable square footage of dwelling space further limiting density along canyon rims.
Lots in High and Very High Fire Hazard Severity Zones that are on cul-de-sacs or roads with a single point of ingress/egress will be ineligible for the Bonus ADU Program. This a bit of a compromise as the bonus program should be eliminated from all VHFHSZ until comprehensive evacuation plans are developed by the city. The labyrinth of streets in Mission Hills is of particular concern.
4-foot side and rear yard setbacks will be required for all ADUs in high fire hazard zones. Zero-foot setbacks will remain for ADUs 16 feet tall or shorter outside of high fire hazard zones. This safe and sane distance is good, though some damage has already occurred ADU are too close to neighboring structures to allow for firefighter access. The new ordinances will not enforce changes to previously built structures nor building permits already issued.
ADUs under 750 sf will pay for infrastructure through a Community Enhancement Fee. This will help offset the dire funding shortage for fire stations.
All Bonus ADUs will be required to have fire sprinklers. Developers should note that not all neighborhoods have sufficient water pressure to support fire sprinklers.