Check your property to get zoning info & price quotes for ADU feasibility & design services:
City Hint: The city has not yet responded to requests for ADU permit volumes for the past year, but they will be provided here once response has been received.
Number of ADUs allowed:
One ADU per lot. The lot upon which the ADU is to be located must contain a single-family residence.
AB68 & AB881 Update: Properties which convert existing space to create ADUs may be eligible for one ADU -AND- one JADU.
Types of ADUs allowed:
Attached, detached and junior ADUs are allowed.
Per state requirements.
AB68 & AB881 Update: Properties will not be subject to minimum lot standards by ordinance or of the applicable zoning district.
Detached ADUs may not exceed 1,400 square feet in floor area. Attached ADUs may not exceed 30% of the floor area of the primary dwelling (not including the garage area).
AB68 & AB881 Update: Properties will be allowed up to 850 square feet for a one bedroom or up to 1,000 square feet for a two bedroom ADU.
Setback requirements as specified in the Hillsborough Municipal Code for all residences. (Review the Development Standards information available online at www.hillsborough.net/planning/informational_handouts.asp).
AB68 & AB881 Update: The maximum required setback for a detached new construction ADU shall be no more than 4 feet from the rear or side property lines.
Parking: ADUs with one or two bedrooms require one parking space, and ADUs with three or more bedrooms require two parking spaces in addition to those required for the primary dwelling. These parking spaces may be unenclosed and cannot be in tandem. Exceptions to the parking requirements may be granted for ADUs including two or more bedrooms.
AB68 & AB881 Update: Properties which convert an existing garage will not be subject to replacement parking requirements.
Per state requirements.
Shape, materials and style:
New construction/exterior changes (if any) should be designed to be compatible with the architectural style and detailing of the primary unit.
Height of the ADU will be determined by the maximum height of the underlying zone.
For the required approval by the Planning Division, the Planning staff can approve most new ADUs administratively. If staff approval is not possible, the application will require approval by the Town’s Architecture and design review Board.
After approval from the Planning Division is secured, construction drawings may be prepared and submitted for the Building Permit application.
Number of Bedrooms:
Not specified by State Standards.
The ADU may accommodate an extended family, a caregiver, or it may be rented. Either the ADU or the primary dwelling may be rented, but not both at the same time unless both are rented to the same party.
That the ADU may not be sold separately.
SB13 Update: Owner-occupancy requirements for ADUs will be voided statewide for 5 years.
Local health officer approval where a private sewage disposal system is being used, if required. (State requirements)
There are no fees for the Planning Division review and there are no Building Permit fees for second units; Building Division plan-checking and other related fees do apply.
SB13 Update: Local impact fees for ADUs will be reduced substantially statewide.
The term “second unit” means a residential dwelling unit that provides complete independent living facilities for one or more persons and is located on the same lot as the main house (called the “primary dwelling”). The second unit includes permanent provisions for living, sleeping, eating, cooking, and sanitation.
The second unit must be constructed within the allowable maximum permitted floor area (FAR) and lot coverage of the applicable zoning district.
Conversion of Existing Space
Conversion of existing residential space (where there is no new construction proposed):
To secure approval of the conversion of existing space, first secure Planning Office, then Building
1. To secure Planning approval of the second unit, submit a completed Second Unit application,
demonstrate (with photos, a site plan, etc.) there is sufficient parking on the property for both the
primary and the second unit, and complete the request for the preparation of the document (for which
there is a fee for the City Attorney’s Office) to be recorded to alert future owners of the regulations
regarding a second unit. Submit these items to the Planning Division for approval. Once evidence of
the recordation of the required document is received, Planning Division approval will be granted.
2. After securing Planning Division approval, the applicant shall obtain all necessary permits and
arrange an inspection by the Building Division. The Building Division will check for any significant
health or safety problems. If there are repairs required, the applicant will work with the Building
Division to correct them. If there are no safety or Code problems, the second unit will be approved.
SB13 Update: Amnesty program to permit unpermitted units will be administered statewide, allowing non-health and safety code violations to be deferred.
ADU Manual / Guide
Residential Building Code:
The California Building Code (CBC) 2016 is adopted with the following amendment(s): 742
Hillsborough Building Department
1600 Floribunda Ave. Hillsborough, CA 94010 Hillsborough, CA 94010
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Read Hillsborough Housing Market Update
California's Housing Future: Challenges and Opportunities - Public ... www.hcd.ca.gov 2017-01-01
Understanding Accessory Dwelling Units and Their Importance www.hcd.ca.gov 2016-12-01
Customer since August, 2018
* upon completion of ADU
CONSTRUCTION COST ESTIMATE
* based on local average price per sqft
Appreciation Estimate = (Base Value: $) / (Home's Living Space: sqft) * (ADU's Living Space: sqft)
Rental Estimate = (Rent Per Sqft: $3.25) * (ADU's Living Space: sqft)
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