FAQs

Where can I learn more about ADUs?

EDC and the City of Evanston collaborated on “Evanston’s Guide to Accessory Dwelling Units”, a 20-page resource generously supported by AARP. You can download the Evanston ADU Guide through this link.

Do I have to live on the property to build an ADU?

No, the property owner does not need to live on the property to build an ADU in Evanston.

What is the maximum height allowed for a detached ADU?

A detached ADU can be up to 28 feet in height for sloped roofs, and up to 20 feet for flat and mansard roofs.

What are the parking requirements for an ADU in Evanston?

You have to maintain or replace the existing parking on your property, but you don’t need to add any additional parking spaces. For example, if you had a 2-car garage prior to your ADU project, your property needs to have two off-street parking spaces upon completion of the project.

What zoning rules affect the dimensions of my ADU?

Your zoning district determines what you can build on your property. It regulates how much of your property can be taken up by buildings (“building lot coverage”), and how much of your property can have impervious surfaces (“impervious surface coverage”).

Additionally, if you are in a Historic District or have a Landmark Property, that will affect your project’s design and construction finishes.

You can look up your zoning district through this free tool offered by the City of Evanston.

What are the biggest costs of an ADU project?

In short, it depends on the project. Constructing a detached ADU is very similar to building a detached single-family home, and our construction cost breakdown often follows the national averages as provided by the National Association of Home Builders (“Share of Construction Cost” column).

Connecting to the water utility can be an added expense on detached ADUs because fire sprinkler systems are currently required in new Evanston dwelling structures. Often, Evanston homeowners’ properties do not have a water service with the capacity to serve both their primary residence and a full ADU with sprinklers. In these instances, homeowners need to upgrade the water service size for their entire property.

What does it cost to build a detached ADU?

Based on construction data from Portland, Oregon, detached ADUs can range from $112,000 to $300,000. Typically, EDC’s detached units fall into a similar range, depending on the design, size, and finishes.

Please note that we value developing an honest, realistic budget with our homeowners— it helps everyone! We can design a unit that aligns with your budget, and you get an ADU that meets your needs.

When we get to the construction proposal with you, we show you the direct cost of labor and materials to EDC and apply our business’ overhead costs to this number.