Wash. Admin. Code § 391-08-100
In computing any period of time prescribed or allowed by any applicable statute or rule, the day of the act, event, or default after which the designated period of time begins to run is not included. The last day of the period so computed is included, unless it is a Saturday, Sunday, or legal holiday, in which event the period runs until the end of the next day that is not a Saturday, Sunday, or legal holiday. When the period of time prescribed or allowed is less than seven days, intermediate Saturdays, Sundays, and legal holidays are excluded from the computation.
Wash. Admin. Code § 391-08-100
Statutory Authority: RCW 28B.52.080, 41.56.090, 41.59.110 and 41.58.050. 98-14-112, § 391-08-100, filed 7/1/98, effective 8/1/98. Statutory Authority: RCW 41.58.050, 28B.52.080, 41.56.090, 41.59.110 and chapters 28B.52, 41.56, 41.58, 41.59, 49.08 and 53.18 RCW. 90-06-070, § 391-08-100, filed 3/7/90, effective 4/7/90. Statutory Authority: RCW 34.04.022, 41.58.050, 41.56.090, 41.59.110 and 28B.52.080. 83-24-031 (Order 83-01), § 391-08-100, filed 12/1/83, effective 1/1/84; Order 77-1, § 391-08-100, filed 1/27/77.