Washington HB 1010: Directing the department of ecology to submit an annual report to the legislature detailing the department's participation in interagency agreements.

Bill Text

AN ACT Relating to creating opportunities for affordable housing 1
by authorizing detached accessory dwelling units in rural areas; 2
amending RCW 36.70A.696, 36.70A.177, 36.70A.130, and 36.70A.210; 3
adding a new section to chapter 36.70A RCW; and creating a new 4
section.5
BE IT ENACTED BY THE LEGISLATURE OF THE STATE OF WASHINGTON:6
NEW SECTION. Sec. 1. The legislature finds that Washingtonians 7
are in a housing crisis and the state needs to produce another 1.1 8
million homes by 2044 to meet its housing needs. The legislature also 9
finds that accessory dwelling units provide affordable housing, can 10
be built quickly, and can provide supplemental income for property 11
owners. Accessory dwelling units are especially needed in rural 12
communities that do not yet have the infrastructure for larger scale 13
development. Therefore, it is the intent of the legislature to 14
provide pathways for the construction of accessory dwelling units in 15
both urban and rural areas.16
NEW SECTION. Sec. 2. A new section is added to chapter 36.70A 17
RCW to read as follows:18
(1) A county may authorize development of detached accessory 19
dwelling units in rural areas on lots of any size, even where 20
H-0110.1
HOUSE BILL 1010
State of Washington 69th Legislature 2025 Regular Session
By Representatives Low, Leavitt, Barkis, Connors, Jacobsen, Couture,
Paul, Timmons, Wylie, Ormsby, Bernbaum, and Hill
Prefiled 12/04/24. Read first time 01/13/25. Referred to Committee
on Housing.
p. 1 HB 1010

otherwise prohibited by the county's comprehensive plan, countywide 1
planning policy, or multicounty planning policy, if the detached 2
accessory dwelling units are subject to development regulations that 3
include the following requirements:4
(a) A parcel may not have more than one accessory dwelling unit, 5
whether attached or detached.6
(b) The detached accessory dwelling unit must be subject to the 7
water supply requirements in RCW 19.27.097 and the following 8
additional requirements:9
(i) The detached accessory dwelling unit may not be located on a 10
parcel that uses a water source that is closed to further 11
appropriation.12
(ii) The detached accessory dwelling unit must use water that is 13
part of the water right for the primary dwelling.14
(iii) Withdrawals of water by each dwelling unit on the parcel 15
must be metered.16
(c) The detached accessory dwelling unit may not be located 17
within, or encroach upon, any existing buffers around critical areas.18
(d)(i) The building permit applicant for the detached accessory 19
dwelling unit must provide documentation demonstrating that the 20
existing or proposed sewage, septic, or on-site sewage system can 21
handle the additional demand placed upon it by the detached accessory 22
dwelling unit.23
(ii) If the detached accessory dwelling unit will be connected to 24
an existing septic or on-site sewage system, the septic or on-site 25
sewage system must be inspected, prior to issuance of the building 26
permit, by a licensed contractor to ensure that the system is in good 27
working order and capable of handling the increased demand placed 28
upon it by the detached accessory dwelling unit.29
(e) The floor area of the detached accessory dwelling unit may 30
not exceed 1,296 square feet, or the square footage that could be 31
authorized by the county as an expansion of the primary dwelling to 32
create an attached accessory dwelling unit, whichever is less. The 33
floor area does not include garages, porches, and unfinished 34
basements.35
(f) The detached accessory dwelling unit must be constructed such 36
that exterior materials, roof form, window spacing, and proportions 37
approximate those of the primary dwelling, except if the detached 38
accessory dwelling unit is a mobile home or manufactured home.39
p. 2 HB 1010

(g) The detached accessory dwelling unit must use the same 1
driveway as the primary dwelling.2
(h) The detached accessory dwelling unit must be sited to prevent 3
loss of land that is defined as "agricultural land" or "forestland" 4
under this chapter.5
(i) A parcel may not be subdivided for the purposes of avoiding 6
the limits on development regulations described in this subsection.7
(2) Subsection (1) of this section is cumulative to other county 8
authority enumerated in this chapter and does not:9
(a) Affect or modify the validity of any county ordinance 10
authorizing accessory dwelling units adopted prior to the effective 11
date of this section;12
(b) Exclude other means of authorizing accessory dwelling units 13
in urban or rural areas, if consistent with this section; or14
(c) Exclude other innovative techniques under RCW 15
36.70A.070(5)(b), 36.70A.090, or 36.70A.177, if consistent with this 16
section.17
(3) The comprehensive plan, countywide planning policy, or 18
multicounty planning policy for any county that authorizes the 19
development of detached accessory dwelling units in rural areas under 20
subsection (1) of this section must be ame