Local ADU Rules

Colma

Last Updated August 29, 2024

ADU Contact:

Colma Planning Department 650.757.8888

Standards
Details
Zones allowed

R, R(s), and C (on properties where there is an existing single-family dwelling)

Lot Restrictions

None

Minimum Lot Size

150 square feet

Min/Max ADU Size

One bedroom or less: 850 square feet
Two bedrooms: 1000 square feet
*50% of main home floor area, unless under 800 square feet (state law allows an ADU up to 800 square feet on every property)
JADUs: 500 square feet

ADU Building Height

Attached: 25 feet
Detached: 16 feet if not within ½ mile of transit, 18 feet if within ½ mile of transit

Setbacks

Conversion of existing area of residence to JADU: No setback requirements
ADU of 800 Square Feet or less:
Side setback: 4 feet minimum.

Rear setback: 4 feet minimum.

Front setback: 19 feet minimum.

Street-facing property line setback: 15 feet minimum

ADU of 800 Square Feet or more:
Side setback: 4 feet minimum

Rear setback: 4 feet minimum.

Front setback: 19 feet minimum

Street-facing property line setback: 15 feet minimum

Parking Requirements

JADUs: No parking required
ADUs: One spot may be required (tandem allowed) No parking required if:
½ mile walking distance from public transit, in a historic district, or one block from a car-share vehicle

on-street parking permits are required but not offered to ADU occupant

Owner Occupancy

JADUs: Required. ADUs: Not required if built recently (2020-2025)

Sample fees from recent permits

No ADUs built at this time

Other requirements

One ADU or one JADU allowed per property. One JADU may be allowed with one ADU if the ADU does not exceed 800 square feet

For detached ADU’s greater than 800 square feet, floor Area Ratio may not exceed 45% and lot coverage may not exceed 50% (exceptions for ADU’s under 800 square feet)

Process

For JADUs, ADUs within existing structures, or detached ADUs 800 square feet or less, only a Building Permit is needed. Attached ADUs or detached ADUs more than 800 square feet are processed through a ministerial ADU Permit approval process. Making an appointment to meet with a planner in the initial stages of the project can help avoid challenges and is highly recommended. Applications will be reviewed by the Planning department and may require revisions. Once Planning has reviewed and provided approvals, if appropriate, the applicant shall apply for a building permit.

Exceptions

ADUs under 800 square feet are exempt from FAR and lot coverage requirements

Wondering what you can build?

Make sure you check out our Learning the Rules page for more step-by-step details
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