The City of Union City has published a Guideline for Accessory Dwelling Units
Requirements for accessory units are summarized below. For more information, see Section 18.32.020 (M) of the Municipal Code, which can be accessed on-line at http://qcode.us/codes/unioncity.
- Attached accessory unit: A building permit is required if the accessory unit is proposed to be attached to the main house, located on the ground floor, and complies with all applicable requirements. Administrative Site Development Review approval by the Planning Division is required prior to building permit issuance if the accessory unit is proposed as a second-story addition or as part of a new principal dwelling.
- Detached accessory unit: Administrative Site Development Review approval by the Planning Division is required prior to building permit issuance if the accessory unit is proposed as a detached structure.
- Accessory units must include a complete independent living facility for sleeping, cooking, and sanitation purposes. A kitchen and bathroom must be permitted for the sole use of the unit.
- Adequate water and sewer service must be available to support the second unit. Separate or combined utilities are allowed.
Setbacks and Location:
- Accessory units shall conform to the same setbacks as required for the principal dwelling unless located above a detached garage.
- If detached, the accessory unit must be located at least 10 feet from the principal dwelling.
- If located above a detached garage, the accessory unit must maintain a minimum 5-foot interior side yard setback, 5-foot rear yard setback, and 20-foot street side yard setback if located on a corner lot.
- The floor area must be between 275 and 640 square feet with a maximum of one bedroom unless the lot is greater than 8,500 square feet in area.
- On lots greater than 8,500 square feet, the maximum floor area of an accessory unit is 800 square feet and a maximum of two bedrooms may be allowed.
- If the accessory unit is created by converting space within an existing single-family residence, the unit cannot contain more than 25% of the floor area of the principal dwelling.
- Detached accessory units are limited to one story and a maximum height of 12 feet unless a higher roof pitch is needed to match the main house.
- If located above a detached garage, the structure must not exceed 30 feet.
- Accessory units must be clearly subordinate to the main house in terms of size, location and appearance.
- The exterior appearance and character of the accessory unit shall reflect that of the main house.
- Outside stairways must meet setback standards and shall not be visible from the public street.
- If a manufactured home is proposed as a accessory unit, it must be identical to the main house in terms of siding and roof materials, roof pitch, roof eaves and color.