ADA COUNTY, Idaho — After 4 days of presentations last week, the Ada County Board of Commissioners is deliberating on a fiscal year 2027 budget that could require a property tax increase, as the county faces shrinking state revenues, rising employee costs, and the financial strain of housing state inmates on local taxpayers' dollars.
Trent Tripple, clerk of the Ada County Board of Commissioners and the county's official auditor, told commissioners that the budget outlook this year marks a departure from recent years.
Since 2021, the county has not taken the full amount of property taxes it was legally allowed to collect, leaving $33 million in taxpayers' pockets — something Tripple said no other county in Idaho has done consistently over that period.
"This year is not the same," he said. "The pressure to keep the county on the correct path will require additional revenues in the form of property taxes or other revenues just to keep the lights on."
Several factors are driving the pressure. Sales tax revenue flatlined in 2024 even as Ada County's population continued to grow, and a new state law redirected a portion of the county's liquor tax revenue sharing to fund Idaho State Police raises, cutting the county's share by several hundred thousand dollars.
The county is also forecasting $1.1 million less in interest revenue for FY27, and keeping employees whole with insurance, software support, and potential cost-of-living increases is expected to drive expenses up by roughly $10 million.
Ada County property taxes have also been used to help cover the cost of housing state inmates. Over the last several years, that bill has exceeded $10 million. While the state provided a small increase to its reimbursement rate, Tripple said even applying the new rate retroactively over the last four years, the county would still have subsidized $8.3 million to house state inmates.
Rapid population growth is adding to the strain. From 2025 to 2026, the county added the equivalent of a small city to its population. State legislation is limiting the county's ability to keep pace — House Bill 389 capped new construction levy authority at 90%, which Tripple said has cost Ada County $12 million in lost levy authority since 2022 and puts more pressure on existing taxpayers.
Commissioners are also contending with a payroll quirk on the horizon. In 2028, the county will face a 27th pay period — a calendar phenomenon that occurs every 11 years for employers on a bi-weekly pay schedule — at a cost of just under $10 million. Tripple proposed spreading that cost over two budget years and setting aside funds annually to avoid a similar hit in the future.
Despite the pressures, Tripple said the county expects to maintain services and retain its workforce with a "very minimal impact on property taxes."
The commissioners are scheduled to return for further budget discussions at 1:30 p.m. on Tuesday. A public budget presentation is scheduled for July 21. The board is then expected to adopt a tentative budget in August and set levies in September.
The Ada County Board of Commissioners' meetings are all livestreamed on Ada County's YouTube.
