Idaho ADU
Building an ADU in Idaho — documented from Day 1.
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Build Journal

A cast-iron water meter cover set into a stone walkway, the words WATER METER raised across its face
Build

Does an ADU need its own water and sewer connection? Post Falls' answer changed.

In July the city told me an ADU has to share the main house's water and sewer. In August Tisha Gallop, a city permit tech, told me that isn't true. Separating runs about $11,000, and there's a cheaper way I didn't know about.

The covered front porch of a blue clapboard house, dark front door with brass hardware, a white wicker chair and a porch swing
Why?

The young man who knocked on my door selling pest control

A young man in his mid-twenties knocked on my door selling pest control. He wants to own a home, and he's thinking about leaving Idaho to afford one. Same math my own sons are doing.

A site diagram of a house and a smaller ADU, with one trench carrying gas and electric between them
Build

Does an ADU need its own gas and electric meter? I called Avista.

Avista quoted about $1,000 to $2,000 to trench for electric and nothing for gas. Then I asked about my other lot in the same city and almost none of it applied.

A scoreboard reading 5 cleared, 8 working on it, 9 still open, above four of the open arguments
Why?

The arguments against more housing, including nine I can't answer

I've been making the case for building more homes in Kootenai County. So I wrote down every serious argument against it, including the ones I lose. Nine of the twenty-two are still open.

The historic Post Falls water tower above the Spokane River, with forested hills behind it
Build

What does it cost to permit an ADU in Post Falls? I asked the city.

The city's fee schedule pointed at $13,000 in water and sewer hookups. For an ADU on a lot that already has a house, the real answer is $1,000 to $2,000 and no connection fee at all.

A line of cartoon hermit crabs trading snail-shell homes on a beach, one wearing an orange traffic cone
Why?

What hermit crabs know about the housing shortage

Hermit crabs line up by size to trade shells, and one new shell moves the whole line up. People do the same thing with houses. Why one more small home helps a family who will never live in it.

A family home and a smaller second home under a warm sky, with the words Room to start a family
Why?

Why am I doing this?

Why I'm building an ADU from zero. It starts with my own sons, who can't reach a home of their own, and the same weight a lot of us are carrying right now.

Illustration of the build tracker page with a progress bar, status chips, and short answers
Build

The Post Falls build now has a live tracker

Every question the build needs answered, a cost ledger with real numbers, and a time ledger for the whole project, on one page that updates as answers land.

3D rendering of the ADU Residence plan, a small house with a covered entry and attached carport
Build

Four free, pre-approved ADU plans sitting on a Kootenai County website right now

The Housing Solutions Partnership publishes four free ADU plan sets, already reviewed by building departments across Kootenai County. Here's what's actually in each one.

Architectural blueprints spread out on a table
Build

Every question an Idaho ADU builder needs answered. What did I miss?

Every question I could think of that an Idaho ADU builder needs answered before they spend a dollar, sorted into four buckets. Now I want to know what I missed.

American flag with a ring of thirteen stars and a 250 seal
Build

Happy 250th, and the gap between Idaho's new ADU law and the Post Falls code

On America's 250th, a side-by-side read of the new state law and my city's code, and the three places they don't agree yet.

The flag of Idaho, a blue field with the state seal at center
Build

Day 1: Starting From Zero

The first post. The day Idaho's new ADU law takes effect and the day I start documenting the whole build from zero.

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