Buying Land in Elmore County, Idaho

Mountain Home AFB: a real, county-adopted overlay district near the base

Mountain Home Air Force Base, home to the 366th Fighter Wing, sits roughly 12 miles southwest of the city of Mountain Home in unincorporated Elmore County. Like other active military airfields nationwide, the Air Force conducts an AICUZ (Air Installations Compatible Use Zones) study around the base, mapping noise contours and accident-potential zones (a Clear Zone plus Accident Potential Zones I and II) and recommending compatible land uses to surrounding local governments. Elmore County has incorporated this into its own zoning code as an Air Base Hazard Zone (ABHZ) overlay district, part of the county's Zoning and Development Ordinance (adopted May 2018, amended February 2023) -- functionally the same kind of local response this site describes for Hill AFB's effect on land use in Davis County, Utah.

What this means for a buyer: land within or near the ABHZ can carry development restrictions or conditions tied to aircraft noise exposure and accident risk that don't apply to otherwise-similar land elsewhere in the county. Before purchasing land in the vicinity of Mountain Home AFB, request the current ABHZ or AICUZ overlay map from Elmore County Land Use and Building and confirm whether your specific parcel falls within it and what restrictions apply -- don't rely on a general sense of "how far" is far enough from the base.

The Mountain Home Plateau Aquifer: a four-decade decline now driving major state action

Outside the City of Mountain Home's municipal water system, the Mountain Home Plateau Aquifer is the primary groundwater source for the surrounding area -- and it has been in serious decline for more than 40 years. The water table has dropped 100 feet or more in some locations, and the aquifer currently runs an estimated pumping deficit of roughly 30,000 acre-feet per year, meaning withdrawals outpace natural recharge by nearly 2-to-1. The severity of this long-term decline led Idaho to designate the Cinder Cone Butte Critical Groundwater Area in 1981 and the broader Mountain Home Ground Water Management Area in 1982 -- among the state's earliest such groundwater-management designations, predating most of the well-known Eastern Snake Plain Aquifer curtailment activity by decades.

This is directly relevant to any land purchase outside the City of Mountain Home that would depend on a domestic well: aquifer conditions here carry documented, long-running stress that is materially different from, and more severe than, typical Idaho groundwater conditions, and the area's Ground Water Management Area status changes the well-permitting process itself -- see the dedicated well-water page below for exactly how. In response, Elmore County has pursued major infrastructure -- most notably the South Fork Boise River Diversion Project, which holds a permit to divert up to 200 cubic feet per second from the South Fork Boise River near Anderson Ranch Reservoir for aquifer recharge and supplemental irrigation, plus a separate 2025-approved permit to draw 20 cubic feet per second from the Snake River, targeting operation as early as 2031. In March 2026, the Idaho Water Resource Board created and funded (with an initial $8 million commitment) a Mountain Home Plateau Aquifer Regional Water Sustainability Program to support this work going forward. This is active, evolving policy, not a resolved situation -- confirm the latest IDWR groundwater-level monitoring data directly with IDWR's Western Region office and Elmore County before assuming a straightforward domestic well on plateau land outside the city.

A zoning code caught mid-update

Elmore County's current Zoning and Development Ordinance dates to May 2018 (amended February 2023), but the county has spent 2024 through 2026 running a comprehensive plan update process called "Envision Elmore," replacing the prior 2014 comprehensive plan, alongside separate Areas of City Impact amendments finalized in late 2025 for both Mountain Home and Glenns Ferry. A related zoning ordinance amendment (ZOA-2026-01) has been discussed to bring the zoning code and map into alignment with the new plan once formally adopted. Given this, treat any zoning district standard as potentially subject to near-term revision, and confirm the current version directly with Elmore County Land Use and Building before relying on it for a transaction.