We service Hillsborough, CA and surrounding areas including zip codes 94010.


ADU in Hillsborough, CA

You might become closer as a family if you all reside in the same home. It might be challenging to maintain that connection as your family expands and everyone needs their own space. ADUs (accessory dwelling units) might be the best solution for your family. Hillsborough, CA, is among the cities that are setting the standard for ADU construction with the Hillsborough pre-approved ADUs program.

As your family grows, you can experience difficulties if yours is like many others. An ADU can provide much-needed additional living space for grown children who are still living at home, aging parents who need care, or other relatives who want to live nearby. You may help your family maintain peace and stability by letting each member have their own place.


The Construction of an ADU

Getting a high quality ADU built is no simple task. The process of planning and building an ADU in Hillsborough, CA, has its challenges, but also has tremendous rewards. We endeavor to make it as simple for you as possible. Here is a brief description of how it works:

  • The first step in establishing whether your project meets the requirements for an ADU is to validate it. To ensure your property conforms to all rules, we’ll inspect it. Answer the question of what can actually be built on your property legally.
  • We’ll work with you to personalize your ADU. There are numerous pre-designed layouts available that can be used right out of the box or tweaked to your needs. There are also many interior packages to choose from, with a variety of design options.
  • Once designed, we’ll acquire your ADU permit and then start building your ADU. Our experienced craftsmen will begin ADU construction to the exact specifications.

The Acton ADU procedure is intended to be straightforward. To ensure that your ADU in Hillsborough, CA, is exactly what you’ve envisioned, we’ll work directly with you at every stage. To start working on your project right now, get in touch with us!


Your ADU Contractors in Hillsborough, CA

Acton ADU, operates in Hillsborough, CA, as well as many other cities in the Bay Area. We have a group of knowledgeable experts who can work with you to design and construct the best ADU for your requirements. We also understand the applicable code requirements and can secure the required permissions for your project.

Adding an ADU can increase your home’s living space, potential income, and value. An ADU may be used for any purpose you can think of, such as a guest house or a home office. You might utilize additional space on your Hillsborough, CA, property that would otherwise go unused by adding an ADU. Call Acton ADU right away to get started!

Questions about ADUs in Hillsborough? Inquire Below
  • Attached
  • Detached
  • Conversion
  • Junior

Get All the ADU Zoning & Regulation Details

CITY OR COUNTYHillsborough, California
DATE UPDATED11/14/2022
ZONINGa. An ADU or JADU subject only to a building permit under subsection C.1. above may be created on a lot in a residential zone
b. An ADU or JADU subject to an ADU permit under subsection C2 above may be created on a lot that is zoned to allow single-family dwelling residential use
TYPES OF ADUSAttached, Detached, Conversion, Junior
STORIESMust comply with underlying zoning requirements.
LOT SIZENo min/max provided the ADU can comply with lot setbacks
MAXIMUM ADU FLOOR AREADetached or attached accessory dwelling units may not exceed 1,400 square feet in floor area
Attached accessory dwelling units may not exceed 50% of the floor area of the primary residence (not including the garage area) or 1,400 square feet, whichever is less
LOT COVERAGEMust comply with underlying zoning regulations, which as per 17.32.060 states:
Lot Size in sq.ft. | Max Square Foot Area of Lot Permitted To Be Covered
Up to 17,500 | 22 sq. ft. for each 100 sq. ft. or portion thereof of net lot area
17,500 to 21,780 | 3,850 plus 15 sq.ft. for each 100 sq.ft in excess of 17,500
21,780 to 32,670 | 4,495 plus 10 sq.ft. for each 100 sq.ft. in excess of 21,780
32,670 to 43,560 | 5,585 plus 6 sq.ft. for each 100 sq.ft. in excess of 32,670
43,560 and over | 6,239 plus 5 sq.ft. for each 100 sq.ft. in excess of 43,560
BEDROOMNo min/max
STORAGENo min/max
KITCHENFull kitchen for attached/detached; efficiency kitchen for JADU
BATHShall provide permanent provisions for sanitation.
Note: Drainage and sewer connections should be assessed on a project by project basis.
SETBACKSa. Side and Rear: An ADU that is subject to this subsection E must conform to minimum four-foot side-and rear-yard setbacks.
b. Front: An ADU that is subject to this subsection E must conform to a twenty-five-foot front setback
Note: Fire Department regulations should be assessed on a project by project basis.
PARKING1. Generally. One off-street parking space is required for each ADU. The parking space may be provided in setback areas or as tandem parking, as defined by subsection K above. The town may restrict tandem parking or parking in setback areas in certain areas or throughout the town if the town finds that such parking configurations are not feasible based upon specific site or regional topographic or fire and life safety conditions
2. Exceptions. No parking under subsection E.9.a. is required in the following situations:
a. The ADU is located within one-half mile walking distance of public transit, as defined in subsection J above.
b. The ADU is located within an architecturally and historically significant historic district
c. The ADU is part of the proposed or existing primary residence or an accessory structure under subsection C.1.a. above
d. When on-street parking permits are required but not offered to the occupant of the ADU
e. When there is an established car share vehicle stop located within one block of the ADU
DESIGNa. The materials and colors of the exterior walls, roof, windows, and doors of the ADU must match the materials and colors of the exterior walls, roof, windows, and doors of the primary dwelling
b. All second-story ADU windows and doors less than 30’ from interior property lines shall either be (for windows) clerestory with the bottom of the glass at least 6’ above the finished floor, or (for windows and for doors) utilize frosted or obscure glass). 
c. Non-conforming units built prior to January 10, 1983 are allowed, however, any alterations or remodeling are limited to the interior of such structures.
Note: Historic Neighborhoods or Districts should be assessed on a project by project basis.
LANDSCAPEa. The ADU and primary dwelling must use the same driveway to access the street, unless otherwise required for fire apparatus access, as determined by CCFD
b. Evergreen landscape screening must be planted and maintained between the ADU and adjacent parcels as follows:
1. At least one fifteen-gallon size plant shall be provided for every five linear feet of exterior wall. Alternatively, at least one twenty-four-inch box size plant shall be provided for every ten linear feet of exterior wall. This paragraph dictates the minimum number of required plantings, not the particular placement of those plantings
2. For a ground-level ADU, plant specimens must be at least six feet tall when installed. As an alternative, for a ground-level ADU, a solid fence of at least six feet in height may be installed
3. For a second story ADU, plant specimens must be at least twelve feet tall when installed
ENTRYWAYSThe ADU or JADU must have an independent exterior entrance, apart from that of the primary dwelling.


SOURCE CODEImportant Note: Rules and regulations are updated and changed frequently. It’s one of our jobs to be up to speed and navigate those regulations. Let us know if our website isn’t up to date or if you have any information that could help. Cheers!


Considering an ADU in Hillsborough, CA? It’s a great way to enhance living space and boost property value. With Acton ADU, you’re partnering with experts who bring your vision to life. From design to construction, we’re with you every step of the way. Reach out today to explore the possibilities.