ADU Rules: Bostonia vs Chula Vista

Who regulates ADUs in Bostonia?

Bostonia is unincorporated San Diego County, so the San Diego County Department of Planning & Development Services regulates ADUs under Zoning Ordinance §6156, not the City of El Cajon.

How big can my Bostonia ADU be?

Under §6156, detached ADUs may be up to 1,200 sq ft and attached ADUs up to 50% of the primary dwelling capped at 1,200 sq ft (at least 800 sq ft must always be allowed). JADUs are capped at 500 sq ft within the existing single-family dwelling.

Can a Bostonia multifamily complex add ADUs?

Yes, but only one approach per property: up to two detached ADUs OR conversion ADUs created within the existing multifamily complex, not both, per §6156.

Do I need a special permit for an ADU in Chula Vista?

No conditional use permit is required. ADUs are approved ministerially through a building permit application with the Development Services Department.

Can I build an ADU on a lot that already has a second unit?

State law allows one ADU and one JADU per single-family lot. Multi-family properties may add detached ADUs equal to 25% of existing units or at least two ADUs.

Are there parking requirements for ADUs in Chula Vista?

Under state law, no additional parking is required if the ADU is within half a mile of a transit stop, within an existing structure, or in other qualifying circumstances.