The Canyon County Assessor’s office reported an average 8.7% increase in residential property assessments for the 2026 tax year, bringing the median assessed value of a Canyon County home to $371,000, according to data released Monday by Assessor Brian Stender. The increase reflects continued strong demand for housing in Nampa, Caldwell, Middleton, and surrounding communities, though the pace of appreciation has moderated from the 12-15% annual increases seen during the 2020-2022 market surge.
The assessment increase does not automatically translate to an equivalent property tax increase — tax rates set by individual taxing districts (cities, counties, school districts, highway districts) determine the actual tax bill. However, higher assessments do expand the tax base from which levies are collected, and homeowners whose properties appreciated faster than the county average may see above-average tax increases even if levy rates remain flat.
Assessment Increases by Area
Property value increases varied significantly across Canyon County. Middleton led with a 10.2% average increase, reflecting intense buyer demand in the bridge community between Ada and Canyon counties. South Nampa neighborhoods near Lake Lowell rose 9.5%, driven by new subdivision activity and proximity to recreation. Central Caldwell saw the lowest increase at 6.8%, as the city’s older housing stock appreciated more slowly than newer construction in outlying areas.
Commercial and agricultural property assessments showed smaller increases. Commercial properties rose an average of 5.4%, while agricultural land assessed under Idaho’s preferential farmland assessment program saw minimal changes, as the agricultural assessment methodology is based on productive capacity rather than market value.
How Assessments Affect Canyon County Property Taxes
Assessor Stender emphasized the distinction between assessment increases and tax increases. “Your assessment going up 8.7% does not mean your taxes go up 8.7%,” Stender said. “It depends on what the taxing districts do with their levy rates. If a district holds its levy flat, your taxes will go up roughly in proportion to how much your property appreciated relative to the district average. But many districts adjust their rates downward when values increase.”
Canyon County’s major taxing districts will set their FY2027 levy rates in September following budget adoption. Historically, Canyon County’s combined tax rate has been among the lowest in the Treasure Valley — a competitive advantage that has attracted both homebuyers and businesses from higher-tax Ada County.
Assessment Appeal Process
Canyon County property owners who believe their assessment is inaccurate have until June 23, 2026 to file an appeal with the Canyon County Board of Equalization. The appeal process is free and does not require an attorney. Property owners should gather evidence supporting their claim, including recent comparable sales data, documentation of property condition issues that affect value, and photographs showing characteristics that the assessor’s records may not reflect.
The assessor’s office provides an online property lookup tool at canyoncounty.id.gov/assessor where property owners can review their assessment details, compare their value to recent sales in their neighborhood, and determine whether an appeal is warranted. Staff members are available to answer questions and walk property owners through their assessment data at the assessor’s office in the Canyon County Courthouse in Caldwell.
What Comes Next
Assessment notices will be mailed to all Canyon County property owners in late May. The Board of Equalization will hear appeals throughout June and July. Property tax bills reflecting the new assessments and FY2027 levy rates will be mailed in November with the first half payment due December 20. Property owners with questions about their assessment can contact the Canyon County Assessor at 208-454-7431 or visit the office on the first floor of the Canyon County Courthouse in Caldwell.