Ada County approves rewrite of zoning code with new solar siting, surety and decommissioning rules

Ada County commissioners on Oct. 28 approved Application 202402581, a repeal-and-replace of Title 8 of the Ada County Code that revises the county’s planning and zoning ordinance and introduces specific standards for centralized power (solar) facilities.

The ordinance adds a new, reserved overlay chapter and a specific section requiring applicants who propose solar on land classified as prime farmland to demonstrate the land is not economically viable for agriculture using one or more established tests. The ordinance also requires irrevocable financial assurance to cover decommissioning, periodic review of surety amounts, county inspection rights, successor liability, and a decommissioning trigger tied to 12 months of ceased commercial generation.

Stacy Dupree, Development Services staff, outlined the standards included in the update, saying staff added criteria that include an NRCS or qualified soil scientist determination showing limiting conditions, documented crop yields at below 50% of the county average verified through farm records or USDA Risk Management Agency data, and profit analyses using State Extension Service enterprise budgets. She also explained the ordinance’s financial-surety provisions, noting that “prior to issuance of any grading or building permits, the applicant shall provide irrevocable financial assurance in an amount sufficient to cover the full estimated cost of decommissioning and reclamation.”

The code allows the county to accept several forms of security (standby letter of credit, bond, or other forms acceptable to the county), requires the county to be named sole beneficiary, and directs that the county may peer-review cost estimates at the applicant’s expense. The ordinance requires an adjustment of the security amount at least once every five years or sooner if the facility is materially modified and obligates owners to file annual reports confirming coverage, updated cost estimates and changes in ownership or configuration.

Commissioners discussed scope and intent. Commissioner Davidson queried whether language referencing ATF approval for shooting ranges should only apply when activities are specifically regulated by ATF. Staff deferred the statutory-detail question to legal counsel. Commissioner Davis said the changes were intended to preserve private-property rights while making explicit the circumstances under which solar on prime farmland could be permitted, and he thanked staff for incorporating the board’s prior direction.

The board moved and approved the ordinance on a voice vote. The approved document also removes multifamily as a conditional use in certain limited office zones, removes a prior requirement to connect to city services within 300 feet following septic failure, eliminates a prior landscape-watering restriction between 10 p.m. and 5 a.m., and updates terminology from “area of city impact” to “area of impact.”

The new ordinance increases the public-notice radius for centralized power facilities to one mile and adds definitions for farmland of statewide and local importance. The board directed staff to publish the clean copy and begin implementing the ordinance; staff also noted they will flesh out the reserved Mile Creek overlay chapter and return with any needed edits.

Copies of the ordinance and the clean replacement Title 8 will be published by the county following signature. Staff said they expect to monitor how provisions function in practice and return to the board if further amendments are needed.