Wash. Admin. Code § 458-16-280
(2) Definitions. For purposes of this rule, the following definitions apply:
(3) Exemption for existing property. All art, scientific, or historical collections owned by associations maintaining and exhibiting the collections to the general public and not for profit, together with all real and personal property owned by these associations and used exclusively to secure, maintain, and exhibit the collections, will be exempt from taxation under the following conditions:
(b) The organization, association, or corporation organized and operated for artistic, scientific, or historical purposes must receive a substantial part of its income from a governmental entity or through direct or indirect contributions of money, real or personal property, or services from the general public. Admission or entrance fees derived from exercising or performing its purpose or function will not be included within the figures used to calculate "a substantial part" of the organization's, association's, or corporation's income.
(4) Exemption for property under construction or soon to be used for an exempt purpose. Property that is being constructed, remodeled, or otherwise prepared to maintain and exhibit art, scientific, or historical collections, may qualify for exemption under certain circumstances. A nonprofit organization, association, or corporation seeking an exemption for property not currently being used for an exempt purpose may qualify if the property will be used for an exempt purpose within a reasonable period of time and proof is submitted that a reasonably specific and active program is being carried out to enable the property to be used to maintain and exhibit an art, scientific, or historical collection.
(a) Acceptable proof of a specific and active building or remodeling program must include, but is not limited to, the following items:
[Statutory Authority: RCW 84.08.010, 84.08.070, 84.08.080, 84.36.389, and 84.36.865. WSR 15-07-021, § 458-16-280, filed 3/10/15, effective 4/10/15. Statutory Authority: RCW 84.08.070, 84.34.141, 84.36.865, 84.52.0502. WSR 09-19-010, § 458-16-280, filed 9/3/09, effective 10/4/09. Statutory Authority: RCW 84.36.865 and 84.36.060. WSR 99-18-008, § 458-16-280, filed 8/19/99, effective 9/19/99. Statutory Authority: RCW 84.08.010, 84.08.070 and chapter 84.36 RCW. WSR 94-07-008, § 458-16-280, filed 3/3/94, effective 4/3/94. Statutory Authority: RCW 84.36.865. WSR 86-12-034 (Order PT 86-2), § 458-16-280, filed 5/30/86; WSR 85-05-025 (Order PT 85-1), § 458-16-280, filed 2/15/85; WSR 81-21-009 (Order PT 81-13), § 458-16-280, filed 10/8/81; Order PT 77-2, § 458-16-280, filed 5/23/77; Order PT 76-2, § 458-16-280, filed 4/7/76. Formerly WAC 458-12-235.]