What is an Accessory Dwelling Unit (ADU)?


What is an Accessory Dwelling Unit (ADU)?

An Accessory Dwelling Unit (ADU) is an attached or detached residential unit that provides complete independent living facilities, including one or two bedrooms, kitchen, and bathroom.

Only one ADU is allowed on a lot, and only if the lot contains an existing or concurrently approved single-family home. The owner of the lot must also live on the lot. ADUs may be rented, but cannot be sold separately from the main home.

California saw a dramatic 62% increase in the number of permits from 2016 to 2017 to over 4,300. The sharp rise in ADU production followed the recent implementation of 3 state legislative bills (Senate Bill 1069, Assembly Bill 2299 and Assembly Bill 2406) which all support ADU development through looser zoning requirements and increased awareness of the issue.

ADUs are a flexible, long-term investment for your property. They can keep family members close, create significant passive income, accommodate overnight guests, and can even help your community address the affordable housing shortage.

Permit Process

These versatile, single family units can be added to a single family home, provided that they meet zoning, and design regulations specific to your jurisdiction.

Most only require a building permit, however some require additional approvals prior to submitting to the building department. Regulations and limitations very by zoning and change regularly so it is always wise to have the planning department review your design before completing plans.

Who best to contact first architect or builder?

Architect + Contractor

The most common way to start is with an architect and then hire the contractor separately.

The benefits of this approach is you have specialized professionals managing each phase of the project. The architect manages design & permitting and the contractor manages building & inspections. This is for homeowners who are willing to spend a bit more time and money on a well thought out design.

Design + Build

Design-Build approach is for homeowners looking for a one stop shop for their project. The contractors provide all services in one package including feasibility, design, permitting, and construction.

This allows homeowners to work through a single point of contact. Generally this approach is for homeowners more interested in saving time and cost than on a custom design.

Project Financing

Regardless of the approach, it is best to source of financing early in the feasibility and design process. Getting qualified for financing will help you determine your budget and gives you more concrete terms to discuss with your architect and or builder before they start.