"Sec. 1   RCW 82.16.050 and 2004 c 153 s 308 are each amended to read as follows:
     In computing tax there may be deducted from the gross income the following items:
     (1) Amounts derived by municipally owned or operated public service businesses, directly from taxes levied for the support or maintenance thereof: PROVIDED, That this section shall not be construed to exempt service charges which are spread on the property tax rolls and collected as taxes;
     (2) Amounts derived from the sale of commodities to persons in the same public service business as the seller, for resale as such within this state. This deduction is allowed only with respect to water distribution, gas distribution or other public service businesses which furnish water, gas or any other commodity in the performance of public service businesses;
     (3) Amounts actually paid by a taxpayer to another person taxable under this chapter as the latter's portion of the consideration due for services furnished jointly by both, if the total amount has been credited to and appears in the gross income reported for tax by the former;
     (4) The amount of cash discount actually taken by the purchaser or customer;
     (5) The amount of bad debts, as that term is used in 26 U.S.C. Sec. 166, as amended or renumbered as of January 1, 2003, on which tax was previously paid under this chapter;
     (6) Amounts derived from business which the state is prohibited from taxing under the Constitution of this state or the Constitution or laws of the United States;
     (7) Amounts derived from the distribution of water through an irrigation system, for irrigation purposes;
     (8) Amounts derived from the transportation of commodities from points of origin in this state to final destination outside this state, or from points of origin outside this state to final destination in this state, with respect to which the carrier grants to the shipper the privilege of stopping the shipment in transit at some point in this state for the purpose of storing, manufacturing, milling, or other processing, and thereafter forwards the same commodity, or its equivalent, in the same or converted form, under a through freight rate from point of origin to final destination; and amounts derived from the transportation of commodities from points of origin in the state to an export elevator, wharf, dock or ship side on tidewater or navigable tributaries thereto from which such commodities are forwarded, without intervening transportation, by vessel, in their original form, to interstate or foreign destinations: PROVIDED, That no deduction will be allowed when the point of origin and the point of delivery to such an export elevator, wharf, dock, or ship side are located within the corporate limits of the same city or town;
     (9) Amounts derived from the production, sale, or transfer of electrical energy for resale within or outside the state or for consumption outside the state;
     (10) Amounts derived from the distribution of water by a nonprofit water association and used for capital improvements by that nonprofit water association;
     (11) Amounts paid by a sewerage collection business taxable under RCW 82.16.020(1)(a) to a person taxable under chapter 82.04 RCW for the treatment or disposal of sewage;
     (12) Amounts derived from fees or charges imposed on persons for transit services provided by a public transportation agency. For the purposes of this subsection, "public transportation agency" means a municipality, as defined in RCW 35.58.272, and urban public transportation systems, as defined in RCW 47.04.082. Public transportation agencies shall spend an amount equal to the reduction in tax provided by this tax deduction solely to adjust routes to improve access for citizens using food banks and senior citizen services or to extend or add new routes to assist low-income citizens and seniors."