Accessory Dwelling Unit Planning Checklist to Get It Right the First Time

An accessory dwelling unit (ADU) is a secondary, self-sufficient residence on the same property as the main residential unit. There are several compelling reasons for building an ADU. These include additional housing options for family members, and elderly parents, the opportunity to generate rental income, make efficient use of existing infrastructure and land, and take advantage of extra flexibility of design and use. However, regardless of the reason for adding an ADU, you must get the planning right to prevent wasting time, effort, and money. Some useful pointers:

Familiarize Yourself with Local Regulations

Before planning your ADU, thoroughly research and understand the local regulations, zoning ordinances, building codes, and permitting requirements specific to your area. These regulations may include restrictions on setbacks, height limitations, lot coverage, parking requirements, and design guidelines. 

Determine Your Goals

Clearly define your objectives for constructing an ADU. Determine whether it will be used to accommodate family members, generate rental income, serve as a home office, or provide housing for caregivers. By clarifying your goals, you can tailor the ADU’s design to meet your needs and make informed decisions throughout the planning process. According to Forbes, an ADU is an excellent way of building wealth by generating rental income.

Budget Considerations

Determine your budget for the ADU project early on. Allocate funds for design, permits, construction, and necessary site improvements. Consider the initial construction costs and potential long-term operational expenses. Developing a realistic budget will help you make informed decisions during the planning and construction stages.

Consider the Size and Layout

Assess the available space on your property and consider the size and layout of the ADU. Determine the number of bedrooms, bathrooms, and the desired living space. Consider the need for a kitchen, dining area, and storage space. Ensure that the layout maximizes functionality and creates a comfortable living environment. You can refer to modern carriage house plans at My ADU.

Assess Access and Privacy

Evaluate the access points to the ADU and its relationship with the primary dwelling. Consider factors like pathways, parking areas, entrances, and outdoor spaces. It’s important to maintain an appropriate level of privacy for both the primary residence and the ADU occupants. Ensure that the design allows for convenient and separate access to the ADU.

Storage and Utility Spaces

Plan for adequate storage space within the ADU! Consider incorporating built-in cabinets, closets, or creative storage solutions to maximize usable space. Additionally, allocate space for utility equipment such as HVAC systems, water heaters, and laundry facilities. Proper planning for these spaces ensures functionality and convenience.

Safety and Accessibility

Prioritize safety measures when designing your ADU. Consider installing adequate lighting, secure entrances, and smoke/carbon monoxide detectors. If you anticipate occupants with mobility challenges, design the ADU to be accessible to ensure a safe and comfortable living environment for all occupants.


Engage with professionals experienced in ADU design and construction, such as architects, designers, and contractors. They can guide you through the planning process, offer valuable insights on local regulations, and help create a cost-effective and functional ADU. Professionals can also ensure that your ADU meets structural requirements and adheres to building codes.