HB1166 – Creates a water quality trading program to help Clean Water Act permittees meet maximum daily temperature discharge limits. (Dead.)
Prime Sponsor – Representative Dye (R; 9th District; Southeast Washington)
Current status – Had a hearing in the House Committee on Environment & Energy January 16th. Still in committee by cutoff.
Next step would be – Dead bill.
Legislative tracking page for the bill.

Comments –
See also HB1381.

Summary –
The bill would require the Department of Ecology to creates a “watershed-based water quality trading program” in which parties with total maximum daily temperature load limits on discharges contributing to raising the heat of water bodies would be allowed to continue to exceed their local limit by reducing heat contributions elsewhere in the watershed. The Department would be required to offer incentives whenever feasible for improvements made by or on behalf of the permittee in the built environment or that otherwise address the urban heat island effect on waters of the state. (There’s a summary of the permit rules about this issue in the staff report for HB1381.)

Though the bill refers to “urban heat island effects,” I think it’s probably reasonable to assume it’s also a response to the EPA’s 2021’s imposition of total maximum daily load limits for temperature in water discharges to the Columbia and the Snake, in Representative Dye’s part of the state.)