City of Diamond Bar ADU Regulations

Everything you need to know about building Accessory Dwelling Units (ADUs) in Diamond Bar, CA.

Overview

The City of Diamond Bar, CA, just passed a new ordinance making it easier for residents to build accessory dwelling units (ADUs) on their property. The goal of the regulation is to increase housing availability in the city while also providing residents with more flexibility in how they use their property.

Building an ADU is a great way to add extra living space to your home, but the process can be complex and confusing. At Vision ADU, we specialize in helping homeowners in Diamond Bar build beautiful and functional ADUs. We’ll work with you to figure out the best design for your needs and budget, pull all the required permits, and manage the construction process from start to finish.

Type of ADUs

The following type of Accessory Dwelling Units (ADUs) are allowed in Diamond Bar, California.

 Attached ADU

An Attacched ADU connects to an existing house, typically through the construction of an addition along the home’s side or rear.

Detached ADU

An Attacched ADU connects to an existing house, typically through the construction of an addition along the home’s side or rear.

Garage Conversion

An Attacched ADU connects to an existing house, typically through the construction of an addition along the home’s side or rear.

Junior ADU

An Attacched ADU connects to an existing house, typically through the construction of an addition along the home’s side or rear.

Diamond Bar Property Requirements

Several rules and regulations must be followed when building an ADU in Diamond Bar. These include:

Number of ADUs Allowed

Single-family lots can build 1 attached ADU or 1 detached ADU with 1 JADU. Multi-family lots are allowed a maxium of 2 detached ADUs.

ADU Size

850 square feet of floor area for a studio/1 bedroom. 1,000 square feet for 2 bedrooms (no more than two bedrooms are allowed)

Height Limit

The maximum height is 16 feet, measured to the top of the roof ridge, and the unit shall not exceed one story.

Number of Bedrooms Allowed

Allows  2 bedrooms.

Setbacks

4 feet from the property line is the minimum side and rear setbacks required for an attached or detached ADU. There are no minimum setbacks requirements for garage conversions or JADUs unless it is needed to ensure fire safety.

Owner Occupancy

JADUs are subject to an owner-occupancy requirement, the property owner must live on the property. All other ADUs built in Diamond Bar after January 1, 2020, but before January 1, 2025, are not subject to any owner-occupancy requirement.

Rental Guidelines

No short term rentals allowed.

Many things make Diamond Bar, California a special place to live. One of the most appealing aspects of the city is its proximity to Los Angeles. Diamond Bar is just a short drive from the hustle and bustle of the city, but it offers a more relaxed and suburban feel.