The new ADU law opened the door. Your sewer line decides if you walk through it.
Idaho's SB 1354 (effective July 2026) makes ADUs legal by right in Coeur d'Alene, Post Falls, and every Idaho city over 10,000 — but the cities kept their sewer standards. They want a video of your lateral before the permit desk signs off. We film it with pro equipment, in the format they require, and get it there on time — the city's inspectors take it from there.
SB 1354 in plain English
As of July 1, 2026, cities can't say no to one ADU per single-family lot — approval is administrative, no owner-occupancy requirement for long-term rentals, and protected sizes up to 1,000 sq ft or 75% of the main house. Both of the bill's primary sponsors are from Coeur d'Alene; this market is the center of Idaho's ADU push.
What cities kept: their water and sewer standards. Sewer adequacy is now one of the few checkpoints left in the approval path — and cities have until February 2027 to rewrite their codes, which means requirements are actively shifting and permit desks are being asked questions they haven't finished answering. Here's how it stands today:
| Jurisdiction | What applies to your ADU's sewer |
|---|---|
| Coeur d'Alene | "One Lot… One Lateral" (Policy #716): your ADU ties into the property's single existing private lateral. Connections and disconnections require a plumbing permit; the Wastewater Department inspects taps with 48-hour notice. The department wants confidence the existing line can carry the added load. |
| Post Falls | ADU must have its own sanitary facilities; plan review with mechanical plans; connection runs through city utility review. |
| Hayden | Where public sewer exists, new buildings must connect to it (City Code 8-2-4) — no new on-site systems if a main is available. |
| Unincorporated Kootenai County | SB 1354 doesn't apply; Accessory Living Unit permit through Community Development, and septic capacity governs — Panhandle Health District approval is needed to add bedrooms or flows. |
Requirements are being rewritten citywide through early 2027 — confirm current rules with your building department. Better yet, send them documentation they don't have to question.
Everything the permit desk and your contractor need, in one visit
1 · Lateral video
A clear camera video of your existing lateral, recorded with commercial-grade equipment in the format your building department expects — before you've spent design money.
2 · Tie-in locate
Exact location and depth of the lateral, painted and flagged to your contractor's spec, so the design ties in where the pipe actually is.
3 · Hand delivery
We've been hand-delivering lateral videos to North Idaho building departments for years — formatted the way permit desks expect, submitted on time, no approval stall.
Cities require a video of your existing lateral before they sign off, and they want it in a format they can review without back-and-forth. We produce exactly that — filmed with commercial-grade equipment, submitted on time, the way your building department expects it. The city's engineers and inspectors review the footage and make the determination.
Planning an ADU, addition, or shop?
Scope and locate the lateral before you finalize the design — it's the cheapest step of the whole project.