Wash. Rev. Code § 54.28.110
Whenever, hereafter, property is removed from the tax rolls as a result of the acquisition of operating property or the construction of a generating plant by a public utility district, such public utility district may make voluntary payments to any municipal corporation or other entity authorized to levy and collect taxes in an amount not to exceed the amount of tax revenues being received by such municipal corporation or other entity at the time of said acquisition or said construction and which are lost by such municipal corporation or other entity as a result of the acquisition of operating property or the construction of a generating plant by the public utility district: PROVIDED, That this section shall not apply to taxing districts as defined in RCW 54.28.010, and: PROVIDED FURTHER, That in the event any operating property so removed from the tax rolls is dismantled or partially dismantled the payment which may be paid hereunder shall be correspondingly reduced.
RCW 54.28.110