ADU Feasibility Studies: A Valuable First Step

As you begin your accessory dwelling unit (ADU) build process, you will eventually encounter the phrase “feasibility study” or “feasibility report.” Feasibility is presented most often as a necessary step that can help inform your decision of whether or not to build an ADU.

What does “feasibility study” actually mean?

In short, a feasibility study or feasibility report determines how realistic an ADU build would be on your property. A feasibility report assesses the viability of a project (or portion of a project), then assigns a cost for actually doing the design and installation. These studies are incredibly useful to avoid spending excessive money on a project that cannot be done in the first place. This initial assessment considers any potential roadblocks and other factors that will affect your build to ensure you have all the necessary information. The main purpose is to reduce the ultimate cost of your ADU build by examining the components first.

Is a feasibility study necessary?

Feasibility studies are not technically a required part of a build. However, they are one of the most valuable steps in an ADU build, since they are designed to save time and money for the homeowner on the overall ADU project. Deciding to forego a feasibility study will most likely lead to a lot of surprises later. Your build might be very wasteful and can be very costly down the road, as it is hard to get an accurate budget without feasibilities.

Many feasibility-associated costs are already included in the cost of building your ADU. A General ADU Study and a Utilities Study are already included in your cost of building with SnapADU, since we want to ensure we can stand by the cost numbers we will provide for your build. The only way to do that is to ensure we have a clear view of the project requirements upfront.

What types of feasibility reports are there for an ADU?

There are a number of different types of feasibility studies that can be used to assess different aspects of your build:

General ADU Study

A general ADU study examines all aspects of a basic ADU build on a flat lot, including the setback and zoning requirements so that we can determine the buildable envelope for the ADU.

Utility Study

A utility feasibility study maps out all existing utilities, such as sewer, water, gas and electric. This assessment helps us place your ADU in a location that will not require significant rerouting of utilities, and ideally, that avoids long utility runs to tie into the existing lines. A utility study also assesses the costs of installing, connecting, maintaining, or removing any of these utilities.

Septic Study

A septic feasibility study accomplishes three things. First, it will map out your existing septic system so that we understand constraints presented; we cannot, for example, locate your ADU on top of leach lines. Second, this study would be used to plan a new septic system for the ADU if this is necessary. Third and finally, a septic study will give you budgeted costs for altering your existing system or designing & installing a new one.

Retaining Wall Study

Exactly how it sounds, a retaining wall feasibility study examines what kind of wall is necessary, plus determines the cost to put this wall into place. Retaining walls are not always necessary, so this study will not apply to every build project. You may also be able to consider different kinds of wall options, including a keystone wall, soil retention wall, or CMU wall.

Grading Study

If you are looking to build out your ADU on a hillside, a grading study will assess  what needs to be done to build your new structure. This includes observing how much dirt needs to be moved and how much it will cost to do so. In some cases when a lot of soil is to be moved, a grading plan may be required by the city. The threshold for the quantify of soil triggers the need for a grading plan; these thresholds vary by jurisdiction.

Right-of-Way Study

A right-of-way study is used if you are seeking to add a new access point to your property. A study is also needed if you do any work outside of your property boundaries (e.g. in “public property,” or the “public right-of-way”). For example, if your ADU will be in the back of your property and away from your driveway, you might look into adding a new road or back entrance to make it easier to access the structure. These studies tend to be a bit more complicated, as it is likely necessary to go to the city to discuss adding this new access point. However, these are all conversations your contractor will be happy to have with you.

Sewer Study

Sewer studies, similar to those mentioned above, are not necessary in every case. This type of feasibility study is employed if you have an existing septic system in place on your property, but would like to connect to your city’s sewer system. Though this may be an intimidating project, the right contractor will work to make it as simple and painless as possible.

How does a feasibility study affect my build?

Depending on the findings of your feasibility assessment, there is always the possibility a build will be determined impossible or unreasonable to undergo. This is where the true value of these studies becomes obvious, as it saves the homeowner from investing significant time and money into a project that is later deemed unviable. It is a safeguard to ensure your money is not wasted or misused.

On the other hand, a more positive feasibility study will confirm the desired ADU can be built, and also offer a preliminary budget of the estimated costs associated with the project. Once you have this budget, you can then determine if this build is a worthwhile investment for your personal goals.

What do I need to do to prepare for a feasibility study?

Short answer: nothing! Yet another reason why feasibilities are so valuable to an ADU project. The entire purpose of the study is to uncover anything that needs to be done to prepare or complete your build, so you get to sit back and let SnapADU do the work for you. We will fill you in along the way, to keep you well informed on the process and make sure you are involved in any key decision points.

Building an ADU is not always as simple as having an idea, putting together plans, and building a structure. There are often many more steps involved in bringing that idea to fruition and many of those steps can be quite costly. Feasibility studies provide a great safeguard of your money between the “idea” and “plans” stage, making them well worth the time and money. It is one of the most effective methods of making this complex process less complicated, less costly, and less intimidating!