Keeping family close without living on top of each other, that’s the whole appeal of an in-law suite. A backyard ADU gives parents or adult kids their own front door, kitchen, and space, while everyone stays on the same property. In Idaho, it’s more doable than ever. Here’s how a backyard in-law suite works and how to build one.
What an in-law suite really is
An in-law suite in the backyard is just an accessory dwelling unit, a small, independent home on the same lot as your main house. Unlike a converted spare bedroom, it has its own entrance, kitchen, and bathroom, so the people living there have genuine privacy and independence. That balance of close-but-separate is exactly why families choose them.
Why families build them
The most common reason is aging parents. A backyard suite lets them stay near family and grandkids while keeping their own space and routine, and it’s often far more comfortable and affordable than assisted living. We wrote a full guide on ADUs for aging parents that’s worth a read if that’s your situation. The same setup works for adult children, a live-in caregiver, or a guest suite that doubles as rental income down the road.
The rules in Idaho
Idaho’s 2026 ADU law made backyard suites easier to permit across the state, though your city still sets the local specifics on setbacks, size, and parking. Our can I build an ADU in Idaho guide covers the statewide picture, and the SB 1354 breakdown gets into the law itself. Always confirm with your local planning department before you design.
A kit is a simple way to build one
Because an in-law suite is compact, a prefab kit is a natural fit. Our 799 sq ft cottage works well as a backyard home, it’s a complete, modern living space with an efficient footprint, and the kit price is fixed before anything ships. That predictability matters when you’re adding a second home to your property. It arrives as a precut package and assembles on a foundation you’ve prepared.
What it costs
A backyard suite’s total cost includes the unit, foundation, utility connections, permits, and finishes. Starting from a cottage kit around $99,500 gives you a known number for the biggest piece. Our total cost guide shows how the full budget comes together.
Thinking about a suite for your family? Give us a call and we’ll help you figure out whether your lot works and what it would take.
Frequently asked questions
Is an in-law suite the same as an ADU?
Yes. A backyard in-law suite is a type of accessory dwelling unit, an independent small home with its own kitchen, bath, and entrance on the same lot as the main house.
Can I build a backyard in-law suite in Idaho?
In most cases, yes. Idaho’s 2026 ADU law made these projects easier statewide, though your city sets local rules. A compact kit home like our 799 sq ft cottage is a common way to build one.
