Where you can position an ADU on your property comes down to setbacks and access: state law generally requires just 4 feet from the side and rear property lines, and you’ll want to keep access to the unit, preserve usable yard, and consider privacy and utility connections. Converting an existing structure can often stay in its current footprint. Here’s how to decide where to put your ADU.
So you’re looking at your property and thinking “How do I position an on my lot?”. California ADU laws allow each residential property to add at least one ADU, even if there isn’t much room to build one. So, odds are there is a place on your property that can house a new ADU, but figuring out the best ADU location is ultra-important. There are a lot of aspects to consider when you’re adding a second home to your property, so you want to make sure you get it right. Below, we discuss the many aspects you should consider when deciding where to locate your ADU.
Here at GreatBuildz, a free service that connects homeowners in the Bay Area, San Diego, Los Angeles, Orange, and Ventura Counties with reliable ADU contractors, we speak to homeowners every day about the right place to locate an ADU on their property – read on to learn more:
What is the Best Location for an ADU in my Backyard?
Determining the best place for an ADU in your backyard starts with the setbacks requirements. In most cases, the state requires back and side yard setbacks to be no more than 4 feet. With that in mind, you might consider placing your ADU as close as possible to the edges of your property (4-5 feet) to maximize the remaining area of your yard.
Next, make sure there is clear and direct access from the street to the ADU location, you don’t want access to the ADU to feel like a maze. Remember, that you need to consider the ADU with regard to its current intended use but also potential uses that a future buyer may want. Because you need to run utilities to your new ADU, choose a location that allows a straightforward location to run the utility conduits & pipes underground from the main tie-in points at the front of the property.
How Far Does an ADU need to be From my Main House?
Every municipality has different requirements concerning the ADU setback from an existing home, so check with your city building department or an experienced ADU architect. In many cases, you’ll need to either attach your ADU to the current residence (they’ll share a wall) or build it 10 feet away from your home. A ten-foot setback from your current house to an ADU is a good starting point.
Can I Position an ADU in my Front Yard, or Does it Have to be in the Back?
In most cases, you will not be allowed to build an ADU is your front yard, but there are several exceptions. Unlike the standard state setbacks of 4 feet for the back and side yards of a property, the state did not dictate the setbacks required for the front yard. Each city has its own zoning requirements for the front yard setbacks and in most cases, they would not allow an ADU to fit in the front yard.
One exception is if your property is large enough that an ADU will fit in front of your home and still meet the required setback. Another scenario is if your garage is already located in the front yard ‘area’ and you choose to convert that into an ADU.
Lastly, a recent California state law, AB 2221, provides that in some cases city’s must reduce their front yard setback requirements if the property has no other location that allows an ADU up to 800sf.
Are there Setback Requirements for Locating an ADU on my Property?
Yes, there are setback requirements for locating an ADU on your property. The State of California has passed laws that require all cities to mandate backyard and side yard setbacks are no more than 4 feet. In terms of the front yard setbacks, the state did not require any specific maximums, so each municipality determines these setbacks based on the zoning of each property. Various state ADU laws require that cities allow an 800sf ADU on every property, even if they have to waive some setback requirements.
Can I Locate an ADU on a Slope or Uneven Ground?
Yes, you can build an ADU on a sloped property, but it requires more costs and planning than a simple ADU on a flat property. Many cities have specific construction requirements and limitations on sloped property, so the first step in building an ADU on a slope is doing research at the building department.
Your building department may require a slope analysis or a soils report. You’ll also need to get an assessment from a civil engineer or architect who can create a site plan and grading plan for your ADU location. Finally, you’ll want to engage a foundation contractor or general contractor with experience building on sloped property.
Just like building a home on a sloped property, an ADU is possible but comes with some complications to overcome. The most important part of planning your ADU on a sloped property is getting the right team in place that is experienced with this type of project and construction.
How do I Choose the Right Orientation to Locate an ADU (sunlight, privacy)?
To choose the right orientation for your ADU on your property, you’ll want to consider, natural light, privacy, access and window/door locations. Locating the ADU’s main living area spaces and windows oriented to the south or west. This should maximize your natural light and temperature.
The location of your ADU and its living space should allow for straightforward access from the occupants parking location to the front door of the ADU. As much as possible, windows of your ADU’s main living space and kitchen should not be placed to have direct views of neighboring properties to provide a better level of privacy.
When choosing the best location, you should consider where the ADU might have its own private yard space. By picking a location that can have a small fenced-in yard area, you would enhance the value and benefits to the ADU occupant. Lastly, consider how landscaping will be added to create the best environment for your ADU location.
Can I Position an ADU over a Garage or Driveway?
Yes, it’s common for homeowners to plan an ADU above a garage or in the place of a driveway. Let’s consider each one separately.
An ADU overa garage is a great option to create an additional living unit while maintaining the space for cars on the property. For ADUs in most locations, the municipality will allow you to build over your garage with a height limit of 25 feet (or the limit per the local zoning ordinance).
There are a few limitations and complications of an ADU over a garage. First, you’ll generally be limited in size because you’re building on top of your garage which is probably not much bigger than 400sf. Next, you’ll need to build a stairway to the second level; the location of which is best on the exterior of the existing garage.
Because your garage wasn’t built to support a second floor above it, you should expect to incur the costs of reinforcing both the garage foundation and its structural framing, adding to the costs of your ADU.
With regard to building an ADU in place of your driveway, it is definitely plausible assuming the location of your driveway (and future ADU) meets the various setback and guidelines of your City. In many cases, removing parking space to build an ADU does not require any replacement parking to be created. But not every property qualifies for this exemption (proximity to public transit), so check with your city’s planning and building departments for guidance.
Are There Restrictions on Locating an ADU Near Utilities like Water or Power Lines?
Yes, there are restrictions on locating an ADU near utilities like power lines, etc. Generally, utility lines like water pipes, drainage channels and power lines have an easement over a portion of the property, precluding the owner from building in this area.
This information is available on city planning maps or on a title report which is available through a title company. Cities and utility companies may also have further requirements regarding setbacks from their utilities, so check with your local building department about those specific guidelines. The utility company may not want you to build too close to their lines and limit their ability to access them for service and replacement.
Also, if you have overhead power lines on your property, your building department or power company may preclude you from building an ADU directly under their lines. Inquire about this before you start your ADU planning because they could require you to pay for the relocation of one of their overhead powerlines.
Locating an ADU – Access and Pathways
You’ll want to ensure there is good access and a clear path to your ADU from the occupant’s parking spot and/or an adjacent street. Placing the ADU as close as possible to an existing walkway or place of access is ideal; or at least making the front door of the ADU as accessible as possible.
Even if you’re building an ADU for personal use and plan to access it only through your main home, you might still consider the ADUs access for future buyers of your property. If they decide to rent this ADU, how will a tenant be able to get from their parking spot to the ADU front door? Walking through the backyard of the main home wont be an ideal access solution.
Positioning an ADU – Impact on Outdoor Spaces
Ideally, building an ADU doesn’t require the entire backyard of your property, and you can locate it in a place to save as much of your yard as possible. Most single family home owners cherish having some private yard space; as opposed to living in an apartment or condo.
If possible, consider locating your ADU as close to the property edges as possible (4-5ft from the property/fence lines). This will help save as much of your yard as possible. You’ll have to balance that with the possibility that your ADU might then be close to your neighbors’ property and may have a direct view of their yard (if you don’t have a high enough fence).
Deciding between a one-story and two story ADU will make a big difference in how much of your yard you’ll have to use for the unit. Obviously a two-story unit will allow you to save much more of your yard space. Conversely, a two-story unit will likely have windows that overlook your neighbors yard which may not be ideal for you.
Locating an ADU – Utility Connections and Infrastructure
Although you cannot build too close to the existing utility infrastructure, if any, on your property, you also want to be close enough to connect your ADU to those same lines. Your ADU will need to tap into the power lines, water lines, waste/sewer lines and potentially gas pipes.
In most cases, the nearest connection point to the underground utilities is in the front of your property (front yard). So if you have a very long property, locating your ADU in the very back of your property may require you to run very long pipes to connect to your utilities, increasing your costs.
This is most vital to consider for your sewer lines. Sewer waste lines flow using gravity, so you must have enough “fall” between your ADU location and the sewer connection point in your front yard. If your ADU is so far that you cant install a pipe that flows downhill and still connects with the lateral in the front yard, you would be forced to install a sewer pump, which isn’t allowed by all municipalities.
Locating an ADU – Noise and Sound Considerations
If you’re concerned with surrounding noise issues from the neighboring properties or adjacent streets, consider positioning the ADU so that windows (especially bedroom windows) aren’t facing in the direction of the noise source.
Using double or triple-glazed windows and sound insulation in the walls will help lower the volume of the noise from the surrounding areas. You can also use fencing and landscaping to buffer some of the noise pollution.
Locating an ADU – Parking and Driveway Access
As you start planning your ADU, parking for occupants is an extremely important topic to consider. Most ADU regulation doesn’t require additional parking for a new ADU, but you still need to think about where your occupant or tenant will likely park.
Even if the ADU occupant will need to use street parking, you’ll want to create a direct access for them to get from their parking location to the ADU front door. You’ll want to ake sure that the parking for the ADU doesn’t hamper the available parking for the main home.
Locating an ADU for Future Flexibility and Resale Value
For future flexibility and resale value, place the ADU in a location that allows for a range of potential uses, like rental income or multi-generational living. Positioning it with some separation from the main house creates privacy and makes it appealing for future renters or family members. This placement preserves options for selling the property as a two-unit setup, which can enhance its marketability and value.
Frequently Asked Questions
Where can I put an ADU on my property?
State law generally requires a new detached ADU to sit at least 4 feet from the side and rear property lines, with no extra front setback beyond your zoning. Beyond that, position it for good access, privacy, and usable yard, and keep utility connections in mind. A converted garage can usually stay in its existing footprint.
How close to the property line can an ADU be?
A new detached ADU generally needs to be at least 4 feet from the side and rear property lines. If you convert an existing structure like a garage that already sits closer, you can typically keep its current footprint under state ADU law.
Does an ADU need its own entrance?
Yes. An ADU must have an independent exterior entrance separate from the main home, since it is a self-contained living unit. Positioning the ADU and its entrance for privacy and easy access benefits both you and your future tenants.
Choosing the right contractors is essential to a smooth, successful ADU building process that doesn’t go over budget. To be matched with a trusted, pre-vetted ADU contractors, contact GreatBuildz today at 818.317.3567 or visit our website for more information.
