Notes from the field.
The law, the lots, and the builds — written by the people doing the work, in the same plain English we use on site. For the deep-dive numbers, see the cornerstone guides.
What RSA 674:71-73 (HB 577) actually says: one ADU by right on any single-family lot, detached units up to 950 sf, and setbacks that match your house — no drama, no legalese.
The by-right law is statewide, but your setbacks, your district, and your paperwork are local. What actually changes from town to town — and how to look yours up in a minute.
Setbacks, wetlands, septic, access, and the buildable envelope — the same five checks we run on every free zoning review, in the order we run them.
Ledge, slope, septic capacity, tree clearing, and how far the utilities have to run: the site conditions that move a quote, from a builder that prices them every week.
Design, permits, site work, the build, and the walkthrough — what each phase involves, what can stretch it, and why the build itself runs 12–16 weeks.
Yes — if the foundation is in before deep frost. How winter actually changes an ADU schedule, and why starting your paperwork in fall is the smart play.