House passes trailer bill tightening assessment bands, clarifying tax rules and scheduling 2025 property‑tax relief

BOISE, March 24, 2025 — The Idaho House passed House Bill 4-35, a trailer bill with technical and policy changes affecting property assessments, tax reporting and the timing of property‑tax relief. Lawmakers approved the measure on third reading by a 62‑to‑2 vote.

The bill tightens the acceptable assessment ratio range from 90–110 to 95–105, a change proponents said will reduce valuation gaps that have led to litigation. A sponsor said the narrower band moves assessments closer to market value and cited a recent court case in which a difference within 5% would have prevented litigation.

The legislation also clarifies when tax rates take effect, aligns statute‑of‑limitations language so the tax commission generally has three years to audit returns (with fraud exceptions retained), and adjusts how a $330 million education allocation appears in the fiscal record so it is shown in expenditures rather than deducted from revenues.

Most notably for property owners, the bill specifies that $100 million in property‑tax relief will be transferred no later than Aug. 31, 2025, making clear that homeowners will see relief in calendar year 2025 even if the transfers are in the next fiscal year.

Supporters said the package reduces appeals and creates consistent fiscal accounting; floor sponsors said county assessors had been consulted and that the tightening will likely reduce post‑assessment litigation. The bill was sent to the Senate for consideration.

Ending: Supporters described the changes as technical fixes that will reduce litigation and clarify bookkeeping for the state and local governments. The bill now proceeds to the Senate.