San Bernardino ADU Zoning Rules & Permit Guide

ADU Regulations in San Bernardino, California

Updated September 29, 2026

At the base of the San Bernardino Mountains, the city aligns with California's statewide ADU mandates. San Bernardino's Development Services Department processes applications under streamlined state timelines.

Below is a summary of the key zoning rules applicable to Accessory Dwelling Units in San Bernardino as of 2026. Regulations are governed by California's AB 68 (2020), AB 881 (2021), and AB 3182 (2024) which together establish a statewide ADU framework.

Additional Local Requirements for San Bernardino

• ADU by right in all residential zones
• Minimum 150 sq ft
• Conversion of existing structures encouraged
• Building permit required

Frequently Asked Questions About ADUs in San Bernardino

Can I build an ADU in San Bernardino?

San Bernardino permits ADUs under California state law with minimal local restrictions beyond state requirements.

What is the maximum ADU size allowed in San Bernardino?

ADUs in San Bernardino can be up to 1,200 square feet, subject to the property's zoning and lot coverage limits. Always confirm the exact allowed size with the San Bernardino planning department before designing your project.

What are the setback requirements for an ADU in San Bernardino?

ADUs in San Bernardino generally require setbacks of 4 ft rear, 4 ft side. California state law (AB 68) limits local setback requirements to 4 feet for existing structures, but always verify with local zoning.