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Everything you need to know about ADUs in Louisville

Here’s need-to-know info on a “mother-in-law suite,” carriage house, or basement apartment on your property.

A hand-drawn rendering of a small blue cabin

The Imagine This ADU is a pre-approved plan for a single-story, 1-bedroom, 760 sqft cottage.

Photo via Louisville Metro.

If you’ve ever wanted to build an extra apartment in your basement or above your garage, you’re not alone. Louisville has some specific rules + regulations when it comes to putting up an Accessory Dwelling Unit, aka ADU. So here’s what you need to know before you a-d-d an A-D-U.

What is an ADU?

Any smaller, secondary residential unit located on the same lot as a main residence qualifies as an ADU. They can be attached to the main dwelling, like a “mother-in-law” suite or a garden apartment, or detached, like a carriage house or a renovated garage. Either way, ADUs have to follow some rules:

  • ADUs can’t exceed the height of the main dwelling.
  • The maximum square footage is 800 sqft or 30% of the main dwelling, whichever is greater.
  • ADUs cannot be used as short term rentals — no AirBnB or VRBOs.
  • You can rent out your ADU, but the owner of the property must reside in the main dwelling.

Bonus: If you’re looking to build an ADU to rent out, there may be funding available through the Louisville Affordable Housing Trust Fund.

A rendering of a small house in a green yard

Studio MAYO is a pre-approved plan for a customizable ADU that can include up to two full bedrooms and a covered porch.

Photo via Louisville Metro.

Let’s build it

You’ll need to follow these steps if you want to built an ADU on your property:

  • Check how your property is zoned. ADUs are allowed in most residential zoning districts.
  • Contact an architect to discuss a plan — the city offers three free pre-approved plans to get you started.
  • Submit your plan and application, even if you’re using a pre-approved plan.
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