Campbell ADU Permit & Building Guide
Building an Accessory Dwelling Unit (ADU) in Campbell is one of the most rewarding investments a homeowner can make. At Apex Homes, we have helped families create extra living space, generate reliable rental income, and boost property value, all within a streamlined process that can take as little as five months. Whether you are considering a backyard home or unit for multigenerational living, Campbell offers excellent opportunities for ADU development.
ADU Regulations in Campbell
Campbell allows ADUs on both single-family and multi-family lots, but the rules vary slightly depending on your property type.
On single-family lots, homeowners can build one detached or attached ADU as well as one Junior ADU (JADU). Detached units may be up to 1,200 square feet, while attached units are limited to 50 percent of the main home’s living area, up to the same maximum size. JADUs, which are created by converting existing space inside the home, can be up to 500 square feet.
Setbacks and height rules are also important. Smaller units—up to 850 square feet or two-bedrooms ADUs under 1,000 square feet—requires only a four-foot setback from side and rear property lines. Units built above garages requires a five-foot setback. Detached ADUs within setback areas are limited to 16 feet in height while attached units outside setbacks can go up to 25 feet.
For multi-family lots, the city allows up to two detached or attached ADUs, each up to 1,200 square feet. Detached units can reach 18 feet in height and must maintain at least six feet of separation from other structures.
The Campbell ADU Permitting Process
The permitting process in Campbell follows California’s streamlined, ministerial approval path for ADUs. Homeowners start by reviewing the city’s ADU guidelines and confirming zoning compliance. Next comes the preparation of architectural plans, a site plan, and a Title 24 energy report. Once ready, the full application is submitting online through Campbell’s MyGovernmentOnline (MGO) portal.
By state law, the city must review and respond to ADU applications within 60 days. Once approved, you can move forward with construction, inspections, and final approvals through the same portal. While not required, Campbell encourages a pre-submittal consultation with the Planning Division, which can help clarify requirements and reduce surprises later in the process.
Pre-Approved ADU Plans in Campbell
One of the biggest advantages for homeowners in Campbell is access to the city’s Pre-Approved ADU Program. These plans are created by licensed architects and meet all local and state building codes. By choosing a pre-approved design, homeowners can save on design costs and reduce permitting time, making it much faster to start construction. These plans are especially well-suited for detached backyard ADUs, which are among the most popular choices for Campbell homeowners.
Currently, Campbell’s pre-approved models include:
Why Build an ADU in Campbell?
Campbell is a vibrant community tucked into the heart of Silicon Valley, just southwest of San Jose. Like much of the Bay Area, it faces a persistent housing shortage, which creates a strong demand for well-designed rental units. A thoughtfully built ADU in Campbell can easily rent for $2,000 to $3,500 per month, depending on size and finishes. Professionals working in nearby tech companies, students, and retirees alike look for modern, private housing options, making ADUs a reliable source of long-term rental income.
The financial benefits don’t stop at monthly rent. Adding an ADU can increase a home’s value by 15 to 30 percent or more. Appraisers count ADUs as part of the property’s usable living space, and buyers increasingly see them as a valuable assets. With Campbell’s desirable school districts and established neighborhoods, homes with ADUs often stand out in the market.
For many homeowners, though, the most meaningful advantages of an ADU is the flexibility it brings to family living. An ADU can house aging parents who want independence while staying close to loved ones, provide a private space for extra living, or serve as a comfortable home for a live-in caregiver. Guests and long-term visitors also benefit from the privacy and convenience of their own dedicated space.
For more detailed information or specific guidance, we can book a free consultation with an Apex Home ADU expert. Let us help you transform your property with a thoughtfully planned ADU today!