---
type: "Bill"
title: "relative to modifying the definition of ADUs."
description: "relative to modifying the definition of ADUs."
jurisdiction: "us/states/nh"
legislature: "New Hampshire General Court"
session: "2025"
identifier: "HB 577"
citation: "New Hampshire HB 577 (2025)"
classification: ["bill"]
subjects: []
status: "enacted"
primary_sponsors: ["Joe H. Alexander"]
version_count: 1
action_count: 17
vote_count: 0
first_action: "2025-01-16"
last_action: "2025-07-22"
source: "openstates"
source_identifier: "ocd-bill/4e1d7fd6-5699-4e60-8a67-78debc398d68"
source_url: "https://www.gencourt.state.nh.us/bill_status/legacy/bs2016/bill_docket.aspx?lsr=0119&sy=2025&sortoption=&txtsessionyear=2025"
source_hash: "59971eb8f3dd58377e61fe58b6c1c6c65ebd21438e6f9cf3c3e47491416e3026"
vintage: "2026-07-01"
source_snapshot: "https://data.openstates.org/daily/2026-07-01/public.pgdump"
retrieved_at: "2026-07-06"
confidence: "reported"
tags: ["legislation", "bill", "us-nh"]
---

# New Hampshire HB 577 (2025) — relative to modifying the definition of ADUs.

## Version chain

The bill's text revisions, in order — the diff chain from filing to enrollment.

1. **Amendment #2025-2874e** (committee substitute) — [source](https://www.gencourt.state.nh.us/bill_status/legacy/bs2016/billText.aspx?sy=2025&id=2025-2874e&txtFormat=amend)

## Sponsors

- Joe H. Alexander — primary (person)
- Alissandra Murray — cosponsor (person)
- Dan McGuire — cosponsor (person)
- Daniel E. Innis — cosponsor (person)
- Hope E Damon — cosponsor (person)
- Jessica Grill — cosponsor (person)
- Joe Sweeney — cosponsor (person)
- Keith R. Murphy — cosponsor (person)
- Lisa R Mazur — cosponsor (person)

## Timeline

The legislative action history — every referral, reading, and vote.

- **2025-01-16** Introduced (in recess of) 01/09/2025 and referred to Housing HJ 3 P. 17 `introduction, referral-committee`
- **2025-01-29** Public Hearing: 02/04/2025 10:00 am LOB 305
- **2025-02-05** Full Committee Work Session: 02/11/2025 10:00 am LOB 305
- **2025-02-26** Executive Session: 02/11/2025 10:00 am LOB 305
- **2025-02-26** Committee Report: Ought to Pass with Amendment # 2025-0449h 02/18/2025 (Vote 18-0; CC) HC 14 P. 10 `committee-passage-favorable`
- **2025-03-06** Amendment # 2025-0449h: AA VV 03/06/2025 HJ 7 P. 15
- **2025-03-06** Ought to Pass with Amendment 2025-0449h: MA VV 03/06/2025 HJ 7 P. 15 `committee-passage-favorable, passage`
- **2025-03-11** Introduced 03/06/2025 and Referred to Commerce; SJ 7 `introduction, referral-committee`
- **2025-03-18** Hearing: 03/25/2025, Room 100, SH, 10:45 am; SC 14
- **2025-05-13** Committee Report: Ought to Pass, 05/15/2025, Vote 5-1; SC 21A `committee-passage-favorable`
- **2025-05-15** Ought to Pass: MA, VV; OT3rdg; 05/15/2025; SJ 13 `committee-passage-favorable, passage`
- **2025-05-15** Sen. Fenton Floor Amendment # 2025-2162s, AF, VV; 05/15/2025; SJ 13
- **2025-06-27** Enrolled Bill Amendment # 2025-2874e Adopted, VV, (In recess of 06/26/2025); SJ 18 `amendment-passage`
- **2025-06-27** Enrolled Bill Amendment # 2025-2874e: AA VV (in recess of) 06/26/2025 HJ 18 P. 57
- **2025-07-02** Enrolled (in recess of) 06/26/2025 HJ 18 P. 59
- **2025-07-02** Enrolled Adopted, VV, (In recess 06/26/2025); SJ 18 `enrolled`
- **2025-07-22** Signed by Governor Ayotte 07/15/2025; Chapter 197; eff. 07/01/2025 HJ 18 `executive-signature`

## Source

OpenStates / OpenCivicData bulk snapshot [2026-07-01](https://data.openstates.org/daily/2026-07-01/public.pgdump); origin `ocd-bill/4e1d7fd6-5699-4e60-8a67-78debc398d68`. Confidence: reported (aggregated from official New Hampshire legislature records).