(1)(a) Each applicant for a building permit of a building necessitating potable water shall provide evidence of an adequate water supply for the intended use of the building. Evidence may be in the form of a water right permit from the department of ecology, a letter from an approved water purveyor stating the ability to provide water, or another form sufficient to verify the existence of an adequate water supply. An application for a water right shall not be sufficient proof of an adequate water supply.

(b) In a water resource inventory area with rules adopted by the department of ecology pursuant to RCW 90.94.020 or 90.94.030 and the following water resource inventory areas with instream flow rules adopted by the department of ecology under chapters 90.22 and 90.54 RCW that explicitly regulate permit-exempt groundwater withdrawals, evidence of an adequate water supply must be consistent with the specific applicable rule requirements: 5 (Stillaguamish); 17 (Quilcene-Snow); 18 (Elwha-Dungeness); 27 (Lewis); 28 (Salmon-Washougal); 32 (Walla Walla); 45 (Wenatchee); 46 (Entiat); 48 (Methow); and 57 (Middle Spokane).

(c) In the following water resource inventory areas with instream flow rules adopted by the department of ecology under chapters 90.22 and 90.54 RCW that do not explicitly regulate permit-exempt groundwater withdrawals, evidence of an adequate water supply must be consistent with RCW 90.94.020, unless the applicant provides other evidence of an adequate water supply that complies with chapters 90.03 and 90.44 RCW: 1 (Nooksack); 11 (Nisqually); 22 (Lower Chehalis); 23 (Upper Chehalis); 49 (Okanogan); 55 (Little Spokane); and 59 (Colville).

(d) In the following water resource inventory areas with instream flow rules adopted by the department of ecology under chapters 90.22 and 90.54 RCW that do not explicitly regulate permit-exempt groundwater withdrawals, evidence of an adequate water supply must be consistent with RCW 90.94.030, unless the applicant provides other evidence of an adequate water supply that complies with chapters 90.03 and 90.44 RCW: 7 (Snohomish); 8 (Cedar-Sammamish); 9 (Duwamish-Green); 10 (Puyallup-White); 12 (Chambers-Clover); 13 (Deschutes); 14 (Kennedy-Goldsborough); and 15 (Kitsap).

(e) In water resource inventory areas 37 (Lower Yakima), 38 (Naches), and 39 (Upper Yakima), the department of ecology may impose requirements to satisfy adjudicated water rights.

(f) Additional requirements apply in areas within water resource inventory area 3 (Lower Skagit-Samish) and 4 (Upper Skagit) regulated by chapter 173-503 WAC, as a result of Swinomish Indian Tribal Community v. Department of Ecology, 178 Wn.2d 571, 311 P.3d 6 (2013).

(g) In other areas of the state, physical and legal evidence of an adequate water supply may be demonstrated by the submission of a water well report consistent with the requirements of chapter 18.104 RCW.

(h) For the purposes of this subsection (1), "water resource inventory areas" means those areas described in chapter 173-500 WAC as of January 19, 2018.

(2) In addition to other authorities, the county or city may impose additional requirements, including conditions on building permits requiring connection to an existing public water system where the existing system is willing and able to provide safe and reliable potable water to the applicant with reasonable economy and efficiency.

(3) Within counties not required or not choosing to plan pursuant to RCW 36.70A.040, the county and the state may mutually determine those areas in the county in which the requirements of subsection (1) of this section shall not apply. The departments of health and ecology shall coordinate on the implementation of this section. Should the county and the state fail to mutually determine those areas to be designated pursuant to this subsection, the county may petition the department of enterprise services to mediate or, if necessary, make the determination.

(4) Buildings that do not need potable water facilities are exempt from the provisions of this section. The department of ecology, after consultation with local governments, may adopt rules to implement this section, which may recognize differences between high-growth and low-growth counties.

(5) Any permit-exempt groundwater withdrawal authorized under RCW 90.44.050 associated with a water well constructed in accordance with the provisions of chapter 18.104 RCW before January 19, 2018, is deemed to be evidence of adequate water supply under this section.

Intent—2018 c 1: See note following RCW 90.94.010.

Effective date—2018 c 1: See RCW 90.94.900.

Purpose—Effective date—2010 c 271: See notes following RCW 43.330.005.

Section headings not law—1991 sp.s. c 32: See RCW 36.70A.902.

Severability—Part, section headings not law—1990 1st ex.s. c 17: See RCW 36.70A.900 and 36.70A.901.