Are you thinking about building a mother-in-law suite in the Bay Area? Recent changes to California state law have made it easier than ever before to get approved for the construction of a mother-in-law suite — or accessory dwelling unit — on your property or attached to your current residence. Before you start building an in-law suite, it’s important to know the rules, regulations and restrictions before proceeding with the design and construction phases. In this article, the ADU builders at Top Home Builders reveal everything you need to know about building mother-in-law suites from permits to planning to construction and even renting out the finished product.

Understanding Mother-in-Law Suites

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Mother-in-law suites or ADUs, are housing units built on residential properties alongside existing single or multi-family homes. This type of housing goes by several names including “guest house” and “granny flat”. There are several types of mother-in-law suites, typically referred to as attached ADUs and detached ADUs.

This ADU is built separately from the primary residence, usually located in the backyard or side yard.

It could also be the renovation of existing sections of the home such as attics, garages, and basements.

The location and design of your house plans with the mother-in-law suite will all depend on who is going to occupy the space, whether it be family, guests, or renters.

Understanding Property and Zoning Regulations


Recent changes to California property law have made it cheaper and simpler to get the necessary permits for ADU construction. Most residential properties are now cleared for the addition of a mother-in-law suite with a few exceptions.

If your home is a designated heritage building or located in a designated heritage neighbourhood you may be subject to additional rules concerning aesthetic design choices and physical placement of the ADU.

For example, in some neighbourhoods, you might only be allowed to build a detached ADU in the backyard rather than the side yard. Also, if your ADU is an attached addition to your current home, the facade will have to complement the primary residence’s look and meet other aesthetic standards of neighbouring homes.

That’s why it’s important to enlist the help of a certified and experienced ADU builder who can help ensure your project is meeting all local building codes and regulations.

Permits and Legal Considerations


Detached ADUs must be placed in the rear yard of the property, or at least 45 feet from any property lines. In terms of spacing, there must be at least six feet of distance between the primary residence and the ADU.

It’s extremely important to work with an experienced ADU builder who knows their way around local building codes and obtains the proper permits for construction.

The quickest way to get your permits approved is to ensure that your house plans with the mother-in-law suite is designed properly.

You will also need to consider increased costs and coverage for home insurance and that building an ADU can lead to a re-assessment of your property taxes, although that number is unlikely to rise by much with California mandating that no property taxes shall be increased by more than two percent annually.


Designing a Custom Mother-in-Law Suite

Before construction, you must take time to consider the purpose and function of your ADU. Is it for a nanny or a close family member to help take care of the kids? Is this going to be an extra living space for occasional guests and friends?

Or maybe you’re building a rental unit for a little bit of extra income that you can use to pay down your mortgage faster.

The purpose of the ADU will help you decide between an attached ADU or a detached ADU. For example, if you’re designing a nanny flat, you may consider an attached ADU close to the children’s bedrooms.

Detached ADUs or residences for in-laws make more sense than detached ADUs to maximize comfort. Every homeowner has unique needs for privacy, accessibility, and general design considerations.


Maximizing Space and Functionality


Just because mother-in-law suites come with limited square footage, there’s still ample opportunity to get creative with an efficient design that can provide adequate comfort and storage needs.

Utilize an open floor plan to keep the atmosphere bright and airy. Functional spaces such as kitchen countertops should be kept to the outside edge.

Leave ample room in the living room for comfortable and easy entertaining. Use multi-functional furniture and custom storage solutions to make the most of every inch within the suite.

The key is functionality; think about the occupant’s daily routine and how you can maximize the space, accessibility, and functionality of the ADU.

custom living room - ADU remodeling

Renting Out the Mother-In-Law Suite

One of the major reasons why more and more homeowners are building mother-in-law suites is because it opens up an opportunity for additional income. Whether it’s a long-term or short-term rental, that extra cash can be used to help pay down the mortgage on the property’s primary residence.

The rental income produced by your ADU is taxable, however, you can write off the costs of maintenance. All ADU owners must be in full compliance with local landlord regulations and rental agreements.

Hiring ADU Builders and Professionals

Teaming up with a professional ADU builder can save you time and money because these experienced designers and architects know how to navigate the world of permits and zoning regulations that come with ADU buildings in the Bay Area.

Expert ADU planners know how to maximize space and function to design something that’s energy-efficient, durable, and great-looking.

Happy workers

Get Professional Design and Build Services For Your Mother In Law Suite

Mother-in-law suite homes can be a great way to bring generations of family together or it can be a smart way to make some extra income. No matter what your plan is for your mother-in-law suite, enlist the help of professional ADU contractors at Top Home Builders. With years of experience, we navigate the legal considerations for you, taking care of all permits and meetings on your behalf to offer you a stress-free building experience. Contact Top Home Builders right now to book your free consultation.