---
type: "Bill"
title: "Providing a limited property tax exemption for the construction of accessory dwelling units."
description: "Providing a limited property tax exemption for the construction of accessory dwelling units."
jurisdiction: "us/states/wa"
legislature: "Washington Legislature"
session: "2019-2020"
identifier: "SB 6231"
citation: "Washington SB 6231 (2019-2020)"
classification: ["bill"]
subjects: ["HOMES AND HOUSING", "TAX PREFERENCES - EXEMPTIONS", "CREDITS", "DEDUCTIONS", "DEFERRALS", "ETC."]
status: "enacted"
primary_sponsors: ["Kuderer"]
version_count: 3
action_count: 38
vote_count: 2
first_action: "2020-01-10"
last_action: "2020-03-27"
source: "openstates"
source_identifier: "ocd-bill/d9ab98e7-5a86-4bc4-a299-2c0121f0a7c1"
source_url: "http://apps.leg.wa.gov/billinfo/summary.aspx?bill=6231&year=2019"
source_hash: "cdc34dfa409fb7ac64512cf2ff7a92f497ba9fb46ab603cc37c9890865aa1a9e"
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-wa"]
---

# Washington SB 6231 (2019-2020) — Providing a limited property tax exemption for the construction of accessory dwelling units.

## Version chain

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

1. **Bill** (committee substitute) — [source](http://lawfilesext.leg.wa.gov/Biennium/2019-20/Htm/Bills/Senate%20Bills/6231.htm)
2. **Second Substitute Bill** (committee substitute) — [source](http://lawfilesext.leg.wa.gov/Biennium/2019-20/Htm/Bills/Senate%20Bills/6231-S2.htm)
3. **Substitute Bill** (committee substitute) — [source](http://lawfilesext.leg.wa.gov/Biennium/2019-20/Htm/Bills/Senate%20Bills/6231-S.htm)

## Votes

- 3rd Reading & Final Passage (#12) — **94–2** (pass) · lower
- 3rd Reading & Final Passage (#6) — **44–5** (pass) · upper

## Sponsors

- Kuderer — primary (person)
- Darneille — cosponsor (person)
- Dhingra — cosponsor (person)
- Hunt — cosponsor (person)
- Mullet — cosponsor (person)
- Wilson, C. — cosponsor (person)

## Timeline

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

- **2020-01-10** Prefiled for introduction. `filing`
- **2020-01-13** First reading, referred to Housing Stability & Affordability. `reading-1`
- **2020-01-27** HSA - Majority; 1st substitute bill be substituted, do pass. `passage`
- **2020-01-27** And refer to Ways & Means. `referral-committee`
- **2020-01-28** Referred to Ways & Means.
- **2020-03-02** WM - Majority; 2nd substitute bill be substituted, do pass. `passage`
- **2020-03-02** Minority; do not pass.
- **2020-03-02** Passed to Rules Committee for second reading.
- **2020-03-10** Placed on second reading by Rules Committee.
- **2020-03-11** 2nd substitute bill substituted. `substitution`
- **2020-01-27** HSA - Majority; 1st substitute bill be substituted, do pass. `passage`
- **2020-01-27** And refer to Ways & Means. `referral-committee`
- **2020-01-28** Referred to Ways & Means.
- **2020-03-02** WM - Majority; 2nd substitute bill be substituted, do pass. `passage`
- **2020-03-02** Minority; do not pass.
- **2020-03-02** Passed to Rules Committee for second reading.
- **2020-03-10** Placed on second reading by Rules Committee.
- **2020-03-11** 2nd substitute bill substituted. `substitution`
- **2020-03-02** WM - Majority; 2nd substitute bill be substituted, do pass. `passage`
- **2020-03-02** Minority; do not pass.
- **2020-03-02** Passed to Rules Committee for second reading.
- **2020-03-10** Placed on second reading by Rules Committee.
- **2020-03-11** 2nd substitute bill substituted. `substitution`
- **2020-03-11** Rules suspended. Placed on Third Reading.
- **2020-03-11** Third reading, passed; yeas, 44; nays, 5; absent, 0; excused, 0. `reading-3`
- **2020-03-12** Read first time, rules suspended, and placed on second reading calendar. `reading-1`
- **2020-03-12** Rules suspended. Placed on Third Reading.
- **2020-03-12** Third reading, passed; yeas, 94; nays, 2; absent, 0; excused, 2. `reading-3`
- **2020-03-12** President signed. `passage`
- **2020-03-12** Speaker signed. `passage`
- **2020-03-12** Delivered to Governor.
- **2020-03-27** Governor signed. `executive-signature`
- **2020-03-27** Chapter 204, 2020 Laws. `became-law`
- **2020-03-27** Effective date 6/11/2020. `became-law`
- **2020-01-15T18:30:00+00:00** Scheduled for public hearing in the Senate Committee on Housing Stability & Affordability at 01:30 PM
- **2020-01-27T18:30:00+00:00** Scheduled for public hearing in the Senate Committee on Housing Stability & Affordability at 01:30 PM
- **2020-02-20T20:30:00+00:00** Scheduled for public hearing in the Senate Committee on Ways & Means at 03:30 PM
- **2020-03-02T15:00:00+00:00** Scheduled for public hearing in the Senate Committee on Ways & Means at 10:00 AM

## Source

OpenStates / OpenCivicData bulk snapshot [2026-07-01](https://data.openstates.org/daily/2026-07-01/public.pgdump); origin `ocd-bill/d9ab98e7-5a86-4bc4-a299-2c0121f0a7c1`. Confidence: reported (aggregated from official Washington legislature records).