Idaho Passes Major Zoning Reforms: How the Gem State Leads in Housing Policy

Idaho lawmakers have enacted a sweeping set of zoning reforms during the 2024 legislative session, signaling a major shift in the state’s approach to housing policy. While not as catchy as the “Montana Miracle,” the Gem State’s legislative package mirrors the YIMBY (“yes in my backyard”) movement’s priorities, passing multiple bills in a single session.

These reforms reflect broader trends in state-level housing policy, where legislatures are increasingly overriding local zoning restrictions to address affordability and supply shortages. Below is a breakdown of Idaho’s key changes and what they mean for housing policy nationwide.

Idaho’s ‘Starter Home’ Law: A National Model for Small-Lot Housing

The most significant reform is S.B. 1352, Idaho’s new “starter home” law, which requires cities with populations of 10,000 or more to update their land-use regulations. The law mandates that new subdivisions of at least four acres must allow single-family homes on lots as small as 1,500 square feet.

This is a dramatic departure from traditional minimum lot size requirements, which often mandate lots of one acre or more—driving up housing costs by forcing builders to consume excessive land. While over a dozen states considered similar reforms in 2024, Idaho’s policy is among the most aggressive at the state level. For comparison, Texas’ new starter home law caps minimum lot sizes at 3,000 square feet within new subdivisions of at least five acres.

Critics of minimum lot size laws argue they inflate housing prices by limiting density and increasing land consumption. Supporters of S.B. 1352 contend that smaller lots will lower costs for builders and buyers, making homeownership more accessible.

Manufactured Housing Rights Expanded Under H.B. 800

Idaho also passed H.B. 800, a law that allows manufactured homes to be placed in any area where traditional site-built housing is permitted. This reform aligns with a growing national trend of states relaxing zoning restrictions on factory-built homes to reduce housing costs.

Manufactured housing once accounted for nearly a quarter of new homes built annually in the early 1970s. However, its market share declined due to stricter federal regulations, shifting market conditions, and zoning barriers that excluded these homes from residential areas. Recent federal housing legislation under consideration in Congress aims to further loosen building code regulations for manufactured housing, potentially restoring its role as an affordable housing solution.

Combined with state-level reforms like Idaho’s, these changes could help revive manufactured housing as a viable option for affordable homeownership.

Accessory Dwelling Units (ADUs) Unrestricted by Local Zoning

Idaho enacted a law that overrides local zoning laws and homeowner association (HOA) restrictions on accessory dwelling units (ADUs) in residential areas. This reform removes barriers to building secondary housing units, such as backyard cottages or garage apartments, which can provide additional rental income or housing for family members.

Unlike Montana’s ADU reforms—which override local zoning restrictions while preserving private covenant restrictions on accessory units—Idaho’s law takes a more aggressive approach by eliminating HOA barriers entirely. Advocates argue this will increase housing supply and affordability by making it easier to add smaller, lower-cost units to existing neighborhoods.

Six-Story Apartments Allowed with Single Staircase Under New Building Code

The final major reform changes Idaho’s state building code to permit apartment buildings of up to six stories to be constructed with a single staircase. This technical adjustment is expected to reduce construction costs and enable the development of smaller apartment buildings on tighter parcels of land.

Advocates for the change argue that single-staircase designs can lower costs without compromising safety, making mid-rise apartments more financially viable in areas where land is scarce or expensive. The reform reflects a growing recognition that overly prescriptive building codes can unnecessarily inflate housing costs.

Idaho’s legislative package demonstrates how state governments are increasingly stepping in to override local zoning and building codes that restrict housing supply. As more states adopt YIMBY-inspired reforms, the Gem State’s approach may serve as a blueprint for others seeking to address housing affordability through policy.