Provides that farms under twenty acres meeting the income requirements of the current use property tax program for farm and agricultural lands are eligible for current use valuation of the land underlying the residential structures. (See also SB 5327).   Official Text and Analysis.

Extends eligibility for current use valuation to the land underlying the residential structure that is contiguous or on and integral to current use classified agricultural land at least five acres up to 20 acres; requires current use classified agricultural land less than five acres to also meet a gross income requirement of $10,000 in three of the last five years before application in order to be eligible for current use valuation to the land underlying the residential structure; removes the exclusion of tidelands whose sole agricultural activity is aquaculture from eligibility.

Makes the modifications to the open space program a pilot program for Thurston County. The second substitute bill also directs the Joint Legislative Audit and Review Committee to provide a report to the Legislature regarding the pilot program by December 1, 2018.

Adds a ten thousand dollar annual income minimum requirement for agricultural land less than ten acres in the pilot program.

Establishes a pilot program in Thurston County under the current use program for home sites on qualifying farms less than 20 acres. Directs the Joint Legislative Audit and Review Committee to provide a report to the Legislature regarding the impact of the pilot program by December 1, 2018.