The Accessory Dwelling Unit (or ADU) has many names: backyard cottage, in-law unit, or granny flat.ADUs are essentially tiny homes, mostly built for the purpose of renting to family members at lower-than-market rates. While ADUs can be a great source of income, a number of challenges must be addressed before you can build an ADU. Here are 10 things to consider before you get started:

Refer to Property Development Standards

You will have to refer to the property development standards for your area. You need to know if the unit will be eligible according to the local standards. For example, you’ll have to know the density units that are allowed for a given property. Your ADU unit will have to fall within those density constraints. In some areas, the height of your unit will have a maximum, and you will have to meet those limits. A unit may also have to be set a certain distance between the property line or limit access to two utility services. It’s Important to speak to your local government officials to determine the standards that you must follow for the unit.


In some jurisdictions, you may have to provide off-street parking for your ADU unit. You may not have to worry about parking if your unit is close to public transportation systems or if it’s in a district that is architecturally or historically significant. The regulations will be different in your area so you should speak to officials to determine if you should provide a parking space for the new unit.

Access to the ADU

You’ll have to ensure that it’s easy to get to the unit. It has to be safe for the person that is staying in the unit to get to the street. You may need a walkway to get from the unit to the street. The passage to the unit should also be clutter-free between your home and the property line.

building an ADU

Privacy Concerns

You’ll have to take privacy concerns into consideration with the unit. This will all depend upon who is staying there. For example, if your parents are staying there, you may not need as much privacy. However, if you are renting the unit to strangers, you want to ensure that they have complete privacy. You’ll have a stranger living in your yard, so you want to ensure that both what you are doing and they are doing is kept private. You may have to install privacy screens such as plants, trees, fencing, and appropriate window blinds for the structure. You want the living arrangement to be as comfortable as possible for the person or persons that are staying there.

Site Conditions

You need to understand the site conditions where the structure is going to be placed. The backyard might be sloped or flat. You may have areas where rainwater pools. By knowing the site conditions, this can reduce expenses because there might be a few things you have to change. For example, if you build on disturbed soil, the foundation could be damaged as the building settles down. If the soil was already dug previously and filled, then you will have to replace it. if your yard has drainage issues, you’ll have to correct these before you build a new structure. You don’t want to have large pools of water around the new structure when the tenants move into it.

Utility Connections

For most places, you shouldn’t have to install any new utilities. You can usually tap into the water from piping, and you probably won’t have to have other service meters. For example, if you are installing a stove, water heater, or a gas furnace in the new structure, then you can tap into your properties gas lines and then a meter can be a stalled upstream of your existing meter. The plumbing fixtures for the unit can tie into existing plumbing, but the septic system will probably need approval from the health department. Your own septic system probably doesn’t have the capacity to handle additional sewage from more bathrooms. An older septic tank will probably need an upgrade before it is connected to any new unit. All of these issues should be discussed with your local officials to determine what you can and cannot do on your property.

Design Guidelines

The design of the unit will vary between counties and cities. The codes and regulations of your area will determine how you build the structure. Most units will probably require bathrooms as well as kitchens. In most cases, a proper heating system will need to be installed as you can’t just use plugin space heaters. If you don’t understand at the building design standards of your area, you’ll have to consult with Structural and MEP design consultants or your local building department to ensure that everything is installed up to code.

building an ADU

Work with an ADU Contractor

You should work with a contractor that has experienced building this sort of unit. You want to work with a professional that understands what is involved with building the ADU unit. They will also understand the rules and regulations when it comes to building this type of unit. They will be up-to-date with the current ADU buildings and technology and can help you design your unit.

Fire Regulations

You should ensure that you refer to the fire regulations of your area. For example, you may have to have a sprinkler installed in the unit, as this might be mandatory in the area. Speak with your local fire officials and building officials so you know the fire regulations that you should follow when building the unit. Even if it might save you a bit of money by not installing, it’s a good idea to have a sprinkler system in the unit especially if it’s difficult to reach during emergencies. You can also speak to your insurance company as you may be able to reduce costs by installing a system.

Saving Space

You also have a lot to think about in terms of space. The unit itself might be quite cramped, so you should think of storage options, size of appliances, and furniture. You want items that can fit into a tiny home yet still leave space for the occupant. For example, make use of wall-mounted storage as this can reduce clutter. Install shelving and other storage areas where necessary so that there is extra room in the dwelling. You should avoid bulky furniture as this will simply take up too much room. Install tables and chairs that can fold away provide more space when not being used. You can have furniture made that can also act as a storage unit. The more space-saving features you have built into the home, the better off you’re going to be.


An ADU home can be an ideal investment. You have plenty of things to consider before you build one. First of all, you should make sure that the unit is going to be appropriate for your property. You should speak to professionals about the design and construction of the property. Once you have a proper plan in place, you can go build the structure.