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Morgan Hill, California: ADU Regulations

City or County:

Morgan Hill, California

Date Updated:



RE 1, RE 2.5, RE 10, plus others. Junior only permitted in single-family zoning.

Types of ADUs:

Attached, Detached, Junior


Must be compatible with the design and scale of the existing dwelling.

Maximum ADU Floor Area:

For Detached:

RE 10: 1,200 sq. ft.

RE 2.5: 1,000 sq. ft.

RE 1: 900 sq. ft., 1,000 sq.ft. for 2 bedroom

All other zoning districts: 850 sq. ft. for 1 bedroom, 1,000 sq.ft. for 2 bedroom

Attached ADUs shall not exceed 30% of existing living area

Lot Coverage:

Must follow requirements established by the zoning district in which lot is located.




No min/max


Require separate kitchen facilities (permanent range, counters, refrigerator, and sink)


Must provide separate sanitation facilities.

Junior: May be shared with primary residence.


New Utility connections are not required. In areas where septic tank disposal systems are allowed due to lack of sanitary sewer lines, Detached ADUs need separate and independent septic tank sewage disposal systems. In other areas, ADUs shall be connected to the primary unit’s existing lateral line.

Note: Drainage and sewer connections should be assessed on a project by project basis.


At least one space for a studio or one-bedroom secondary unit and a minimum of two spaces for secondary dwelling unit containing two bedrooms, in addition to those required for primary dwelling unit.

Off-street parking spaces for secondary dwelling unit may be uncovered. Secondary dwelling parking may be located within the front, side or rear yard areas.


- ADU is located within one-half mile of Morgan Hill Caltrain station or a bus transit stop with a frequency of service interval of fifteen minutes or less during the morning and afternoon peak commute periods.
- ADU is located within a National Register Historic District or other historic district officially designated by the city council
- When on-street parking permits are required but not offered to the occupant of the ADU
- When there is a car share vehicle pick-up/drop-off location within one block of the ADU

When an existing garage, carport, or covered parking structure is demolished in conjunction with the construction of an accessory dwelling unit, and the zoning code requires that those parking spaces be replaced, the replacement spaces may be located in any configuration on the same lot as the accessory dwelling unit, including, but not limited to, as covered spaces, uncovered spaces, or tandem spaces, or by the use of mechanical automobile parking lifts. 


Detached 16’ or less in height: 4’
Detached >16’ in height: Same as primary dwelling

Note: Fire Department regulations should be assessed on a project by project basis.


No higher than primary dwelling.

Rear Yard Coverage:

Must follow requirements established by the zoning district in which lot is located.


ADU shall be clearly subordinate to the primary dwelling by size, appearance, and location on the parcel.

The design of secondary dwelling unit shall be compatible with design and scale of existing dwelling (using substantially the same landscaping, color, materials and design on exterior) and the general character of neighboring residential properties.

Openings (e.g., doors and windows) on exterior walls that are closest to and face adjacent residentially-zoned properties shall be designed to minimize privacy impacts and maintain access to light and ventilation on adjacent properties.

Note: Historic Neighborhoods or Districts should be assessed on a project by project basis.



Code Source:

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