Plans, Amendments and the 20-Year Clock

Almost every fight over urban renewal is decided months before the hearing, when someone draws a boundary on a map and a consultant writes an eligibility report. By the time the ordinance is on the council agenda, the plan is several hundred pages long and the taxing districts have had 30 days to read it. Knowing the sequence lets you show up when it still matters. What the plan must contain, and how the base value works, is in the property tax course's urban renewal lesson. This one is about the calendar.

Is the area eligible?

Before anything is planned, the council must adopt a resolution finding that the area is a "deteriorated area" or "deteriorating area" and designating it for an urban renewal project (50-2008(a)). The definitions are broad. Besides run-down buildings, they include "defective or inadequate street layout," "faulty lot layout" and "diversity of ownership." The Chapter 29 definition adds predominantly open land where "obsolete platting, diversity of ownership" or similar conditions result "in economic underdevelopment of the area." That is why bare ground at the edge of town, with no buildings at all, can qualify.

One firm limit: agricultural operations and forest land are excluded unless the owner gives written consent, except land that has not been used for three consecutive years (50-2018(8) and (9), and 50-2903(8)(f)). For Magic Valley towns ringed by working farms, that consent letter is worth asking for.

The adoption sequence

1. Draft. The agency prepares the plan, or "any person or agency, public or private" may submit one (50-2008(b)). Developers sometimes do.
2. Planning commission. The council sends the plan to the planning commission, which has 60 days to say whether it conforms to the city's general plan, which most cities call the comprehensive plan. Silence lets the council proceed.
3. Notice. At least 30 and no more than 60 days before final reading, the council publishes notice and sends it, with the plan and the agency's recommendation, to every taxing district that levies in the area (50-2906(3)). For areas created or modified after July 1, 2025, fire and ambulance districts are left out unless the city sends a consent request with this notice and the district adopts a resolution agreeing to be included (50-2906(4)).
4. Hearing. A newspaper notice describes the time, place, area and general scope.
5. Findings and ordinance. The council must find, among other things, that the plan conforms to the general plan and that a feasible method exists to relocate any displaced families. It then adopts an ordinance under the city ordinance procedures in Title 50, chapter 9.
6. Effective date. The revenue allocation provision is retroactive to January 1 of the year the ordinance passes (50-2906(2)). That January 1 roll becomes the base.

The size cap

Under 50-2903(16), the base values of all revenue allocation areas in a city combined cannot exceed 10 percent of the current assessed value of all taxable property in the city. The cap applies only to base value. Acres and increment do not count against it. An area drawn around cheap, empty land can be physically large and still use little of the cap.

Changing a plan

An urban renewal plan "may be modified at any time" (50-2008(e)), but changing a plan with a revenue allocation provision takes an ordinance and a public hearing (50-2906(1)). Since 2016, most modifications reset the base to current value, which shrinks future increment; the exceptions and the annual affidavit are covered in the property tax lesson. Other rules shape amendments too:

• Adding land never extends the deadline. 50-2904 says additions "shall not" extend the original 20-year limit. A one-time expansion of no more than 10 percent of area is the separate limit in 50-2033.
• Removing land returns value. When parcels are de-annexed, 80 percent of the increment above the 2006 level (or all of it for areas formed after 2006) goes on the new construction roll for the taxing districts, under 63-301A(3)(j). The Twin Falls agency processed a plan amendment in 2025 to de-annex roughly 28 acres from its Revenue Allocation Area 4-3, according to its 2025 annual report.

The 20-year clock and its exceptions

50-2904 limits a revenue allocation provision to 20 years from the date the ordinance is approved. The exceptions:

During the bond extensions in (1) through (4), any revenue beyond what the bonds need goes back to the taxing districts pro rata (50-2904(6)). The manufacturing extension in (5) is different: the agency keeps receiving increment until the new termination date.

The Chobani connection

Subsection (5) arrived in House Bill 436, the same 2025 bill that rewrote dissolution. A Chobani lobbyist told the House Revenue and Taxation Committee the provision would help pay for doubling Twin Falls' water and wastewater treatment capacity for the company's roughly half-billion-dollar plant expansion, BoiseDev reported. Rep. Jeff Cornilles of Nampa suggested splitting out the Twin Falls portion and said the bill moved too fast for public input. The bill became law anyway, retroactive to January 1, 2025.

"Controlled by" means a binding lease covering the full extension period. Whether the Twin Falls agency has adopted or will adopt an extension for its Chobani area under this subsection was not confirmed for this lesson; the plan amendment ordinance, if one exists, would say so and would be posted to the Tax Commission registry (lesson 4).

Ending early, and ending on time

An agency's budget for the year before (or including) its termination date must be built specifically for that plan. If current revenue covers all remaining expenses, the agency must adopt a resolution by September 1 notifying the city, county auditor and Tax Commission and recommending an ordinance ending the area by December 31 (50-2903(5)). Areas can also simply be ended by ordinance. Twin Falls' Washington Street South area, created in January 2020, had no planned development and was terminated on August 26, 2024, according to the agency's financial statements.