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Mother In Law Apartment: 8 Key Things To Know

Oftentimes, a mother-in-law apartment is referred to as a mother-in-law suite, guest house or in-law suite. If you're thinking of building a mother-in-law suite, here's what you need to know before you kick off the project.
Key Things To Know About Mother-In-Law Apartment

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A mother-in-law apartment is a common way to offer comfortable housing for relatives and guests to stay in your home and improve the value of your floor plan.

Nearly 20 percent of the population in the United States lives in a multi-generational home, which means that three or more generations live in the same household.

As the cost of assisted living continues to increase, older Americans are deciding to move in with their children and grandchildren.  Instead of taking the extra bedroom upstairs, they are relocating into their private in-law suite.

While a lot of people find it a benefit to have an attached or detached suite for guests, it also can serve as a waste of space (and money) if not properly used. Also, building a mother-in-law suite may imply handling red tape and city rules.

On the contrary, having a separate apartment for an in-law to accommodate all of your guests could be worth the renovation issues. Continue reading to determine whether building a mother-in-law apartment or purchasing a home with one is worth the headache and costs involved.

What does a Mother-in-Law's Apartment Mean?

A mother-in-law apartment also referred to as a mother-in-law suite or an in-law suite, is a separate apartment added into a larger home. Mother-in-law apartments have different floor plans but, in general, contain a bedroom, bathroom, living room, and kitchen. Most of them feature a separate entrance, and some even come with a store personally attached to the garage.

The idea behind this suite is generally to provide older relatives or long-term guests a private and comfortable place to live, even though it is popular to build one majorly for rental.

However, not every mother-in-law apartment has every feature. A mother-in-law’s apartment is added into my house, finished with its bathroom, living room, and one-car garage that is different from the two-car garage use by my wife and me. Yet, it doesn’t feature a separate kitchen, so it is not a completely self-contained apartment.

A mother-in-law suite can either be incorporated into the main building, attached into basement, or built separately on the same property. Some mother-in-law apartments can be legally tagged as Accessory dwelling units (ADUs), which usually enable them to be rented out.

What is involved in Building a Mother-In-Law?

Building a Mother-in-law apartment from scratch may mean going through the difficult zoning regulations of your area and many construction rules. You will need to first determine whether a rentable property or an ADU is even allowed to be constructed in your residential area. City zoning rules or Homeowners Association may not allow the building of secondary dwelling units.

When constructing a Mother-in-law apartment, it is also highly important that you hire an experienced and licensed general contractor to help with any important documentation, permitting, and building needs. 

What is the Basic Layout of a Mother-in-Law Suite?

The following feature may be included in a typical mother-in-law apartment floor plan:

Bedroom: An important feature of a Mother-in-law’s apartment is a nice bedroom. Enough storage space (such as a walk-in closet or huge chest of drawers) for clothing and other individual items is important for long-term occupants.

Full bathroom: Most mother-in-law apartments come with a full bathroom, which includes a bathtub, sink, shower, and toilet, to provide an independent feel for the occupants from the main house.

Private entrance: While not thoroughly required, a separate entrance is a popular feature of Mother-in-law apartments because it offers additional independence and privacy for occupants.

Other home comforts: Mother-in-law apartments can come with extra features as allowed by space, such as a small complete kitchen or kitchenette, a small living space, and a small dining room or area.

What are the Advantages of Having a Mother-in-Law Apartment?

Buying a home with a mother-in-law suite (or constructing one yourself) has its advantages. Below are the many reasons why owners decide to have a mother-in-law suite on their property:

1. Aging relatives

A mother-in-law’s apartment can be a cheaper way to provide housing for an elderly relative, nullifying the need to purchase a separate home or pay for an assisted living center. Also, you will have rest of your mind with certainty that your loved one is nearby. Around 64 million citizens of the USA reside in multigenerational homes, and a mother-in-law’s apartment can make it a lot easier too.

2. Older children

If you have older kids or college-age children who would love to have extra privacy and space than what is offered by a typical bedroom, a mother-in-law’s apartment can be a great option.

3. Rental income

As discussed, some homeowners construct mother-in-law apartments for the sole purpose of renting them out to tenants. Usually, the income gotten by a 1-bedroom accessory living unit can be a great return on the money you spent on constructing it. A lot of homeowners rent their attached units temporarily via platforms like Airbnb, and others lease their units full-time to occupants.

4. Comfortable space for guests

If you like to have family and friends stay over, but don’t want crowds in your kitchen or living areas, a mother-in-law apartment could be a wise idea. You can have guests and still maintain your privacy.

5. Live-in nanny

With the increasing cost of childcare in the past years, the live-in nanny has to turn out to gain more recognition for raising families. A mother-in-law’s apartment can accommodate a live-in nanny while living on the premises throughout the day.

6. Storage

While this is not a good reason to have a mother-in-law’s apartment (building a shed is likely cheaper), it is a popular use. While my wife and I make use of ours to accommodate guests who stay over, we also make use of the closet space in the suit as storage for items we don’t have space for.

And since our children are not allowed in, the bathroom closet in our mother-in-law’s apartment is a perfect place to keep cleaning supplies for the entire household.

What are the Limitations of Having a Mother-In-Law Apartment?

Mother-in-law apartments are not ideal for everyone. Below are a few important reasons why you may not want a house with a Mother-in-law suite:

1. Costly to Build

One of the major limitations to having an attached guest home to your main house is the high costs of the utility. Think about it: together with heating and cooling your home, you will now be paying to also heat and cool your guest house. Not to talk of the fact that you are almost certain to have a crazily high water bill, including higher energy costs.

2. Subject to City Rules

Another reason that many should have a deep thought before constructing a mother-in-law apartment is that it may mean having to tackle the city zoning regulations and tough construction codes. If the main house is located in a historic district, this attachment will be more difficult to achieve.

3. Insurance Costs

These are the third limitation of having a mother-in-law suite. You will have to find out whether your existing homeowner’s insurance policy will also protect an attached living space. If you are renting it out, you may need to buy an extra insurance policy to protect your home properly.

4. Need Additional Upkeep

This fourth limitation to owning a mother-in-law’s apartment means that there will be an increase in your daily upkeep. From cleaning toilets to clearing gutters and vacuuming the floors to replacing light bulbs, keeping a guest home can take a lot of time and money. A lot of people find that costs and continuous upkeep unworthy of the advantages of having a mother-in-law apartment

5. Potential Vacancies

In cases where you don’t have guests, relatives, or renters living in your in-law suite, the unit may remain empty and consume space that you may have loved to use for other activities, such as a basement living room or a backyard space.

Important Checklist for Constructing a Mother-In-Law Apartment

1. Consult Your Local Building Codes

Your local building codes will dictate the features you can include in an in-law apartment. If you are considering building extra, you will often be restricted to a bedroom, bathroom, small sitting area, and kitchen.

Building a full kitchen or detaching a unit from the main building will need different permits or may even be prohibited by local zoning regulations that ban residential areas from constructing rentable properties.

Other popular requirements for a Mother-in-law apartment include:

  • Permanent residence on the property where the Mother-in-law’s apartment will be built.
  • An outside entrance into the apartment, separate from the entrance of the main house.
  • Different water and sewer connections, although most neighborhoods allow 3 overall plumbing connections with a sewer permit.
  • Access to off-street parking, like a garage or driveway.

2. Locate the Perfect Spot for Your in-law Suite

Similar to real estate, in-law apartments all involve three things: location, location, and location. Based on what your city allows, you could convert your attic, garage, basement, and porch to an apartment. To add units to the home, the best location to build one is to use the first floor, perfectly located closer to an existing bedroom.

To have a comfortable living space, the three important Mother-in-law suite rooms to have would include a bedroom, a full bathroom, and a complete kitchen or kitchenette area. This will provide your parent the independence to bathe and cook in the comfort of their suite without affecting your family schedules.

3. Separate the Apartment’s Utilities From Your Main House

Separating the utilities of your Mother-in-law’s suite from the main home will enable you to turn them off if the apartment ever goes without occupants for a long time. And if you later lend the space out to another occupant, you can split the bills with ease.

4. Consider the Current and Future Needs of Your Parents

What are the special needs of your new guest (if any)? It may be wheelchair accessibility or whether they need grab bars for the bath; your in-laws likely plan on aging in place immediately after they move in.

Make sure you are proactive and that their new home is designed to age with the installation of pull-out drawers, shower seats, as well an adjustable sink, together with other relevant amenities.

5. Locate a Certified Contractor

Find a contractor who has constructed Mother-in-law suites before and is a certified specialist in aging-in-place. Contractors that have this designation can be of huge help during the construction process, giving advice and design ideas to ensure your Mother-in-law’s suite is as functional as possible. T

he National Association of Home Builders keeps an accessible database of members who have worked hard to earn their CAPS designation, enabling you to find a specialist in your area and fast.

Does the Value of your Home Increase when you have a Mother-In-Law Suite?

Yes, adding a Mother-in-law suite will likely increase the value of your home. At first, adding more square footage to your main house will lead to a higher listing price when you choose to sell your home. Also, the additional living space is majorly attractive to buyers with large families or those that plan to make additional rental income. The Nest also mentioned that many home buyers are ‘prepared to pay more for a basement and Mother-in-law suite’.

This is based on a survey by the National Association of Realtors. The study discovered that ‘a completed basement and Mother-in-law suite were the two most coveted-after parts of a home that buyers would be prepared to pay more for.’

What is the Cost of Building a Mother-In-Law Suite?

The cost to construct an in-law suite differs by the type of space and the amount of work required to make that space perfect for living. Normally, your Mother-in-law suite should include all you needed for independent living, like a private room, bathroom, living area, and kitchen. Adding all these elements is costly, with the cost of installation calculated to be around $40,000 and $125,000 by a financial expert.

Even though this may seem steep, the one-time cost to construct a Mother-in-law suite is lower compared to the yearly cost of assisted living communities. As revealed by Genworth’s Cost of Care Survey, an average cost of $105,000 will be paid for a private room in a nursing home in the United States per annum.

In the process, the cost of adding a Mother-in-law suite is almost often cheaper than the alternative. And aside from the money aspect, being around family is perfect for the well-being of your parent. 


Whether you are relocating to a home that has a Mother-in-law suite or moving to the guest house, you may need professional assistance with the heavy lifting. To locate a trustworthy and reliable mover, check the comprehensive network of movers on Moving APT. We simplify the quote comparison process from many interstate moving companies, local moving companies near you, and long-distance moving companies, all without charge. All companies performing moves in our network are licensed and insured, so you don’t have to worry.

Dani James

Dani James

Dani James is a copywriter and blogger with more than eight years of experience writing for movers, real estate, and anything to do with getting from point A to point B. When he’s not finding new ways to save on moving costs, he can be found at home with his cat, binge-watching Marvel movies, and looking for new apartments he can’t afford.
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