Tax System Data Updated: March 5, 2018. Tax system data is for the 2017 tax year. Reference data ONLY, contact the Treasurer’s Office for current payoff amount. This data doesn't show any new parcels or splits made since January 1, 2017. Those changes are for tax year 2017. Ownership and "Mail To" address changes are updated for the 2016 current tax year. Current tax data (2017 tax year) can be found by using the Wasatch County Base Map service. Property tax facts are available on the Treasurer's webpage.