Wash. Rev. Code § 82.32.495
(1) If neither the department nor the designated database provider provides an electronic database under RCW 82.32.490, a mobile telecommunications service provider shall be held harmless from any tax, charge, or fee liability in any taxing jurisdiction in this state that otherwise would be due solely as a result of an assignment of a street address to an incorrect taxing jurisdiction if, subject to RCW 82.32.500, the home service provider employs an enhanced zip code to assign each street address to a specific taxing jurisdiction for each level of taxing jurisdiction and exercises due diligence at each level of taxing jurisdiction to ensure that each street address is assigned to the correct taxing jurisdiction. If an enhanced zip code overlaps boundaries of taxing jurisdictions of the same level, the home service provider must designate one specific jurisdiction within the enhanced zip code for use in taxing the activity for such enhanced zip code for each level of taxing jurisdiction. Any enhanced zip code assignment changed in accordance with RCW 82.32.500 is deemed to be in compliance with this section. For purposes of this section, there is a rebuttable presumption that a home service provider has exercised due diligence if the home service provider demonstrates that it has:
(2) Subsection (1) of this section applies to a mobile telecommunications service provider that is in compliance with the requirements of subsection (1) of this section, if in this state an electronic database has not been provided under RCW 82.32.490, until the later of:
[ 2002 c 67 s 12.]
Finding—Effective date—2002 c 67: See notes following RCW 82.04.530.