What exactly does a 2,500-square-foot lot look like?

This story is excerpted from the MT Lowdown, a weekly newsletter digest containing original reporting and analysis published every Friday.

One of the housing affordability ideas currently being batted around by the Legislature is a proposal, House Bill 337, that would force Montana cities to allow home lots as small as 2,500 square feet anywhere they provide municipal water and sewer access.

That’s much smaller than the minimum lot sizes currently enshrined in many local zoning codes — 4,000 square feet in Bozeman, for example, or 20,000 square feet in one of Kalispell’s residential zoning districts. Supporters of the reduction bill say those size requirements stifle development, encourage sprawl and force builders to build larger, more expensive houses.

Opponents, including the Montana League of Cities and Towns, have argued that the Legislature should leave cities alone. In a Facebook post, the league dismissed the bill’s ideas as “California solutions” and warned it would “transform our communities into highly dense, urban settings with insufficient parking and inadequate services.”

But what exactly does a 2,500-square-foot lot look like? We pulled parcel data from the Montana State Library’s Cadastral system to illustrate, using a portion of central Helena not far from the Capitol building. That neighborhood includes a wide variety of lot sizes — some even smaller than the 2,500-square foot threshold.

Many of the lots on these blocks are at or above a comfortable 5,000 square feet, but in a few places homes sit on corner lots or narrow strips sized in the 3,000 to 4,000-square-foot range. Along 10th Avenue, a few modest houses sit in rows on sub-2,500-square-foot lots.

This part of Helena was originally platted in the 1880s, according to Lewis and Clark County records — decades before the adoption of modern zoning codes. As such, many of these homes don’t comply with current zoning rules and wouldn’t be legal to build today without special permission from the city. The city of Helena struck its minimum lot size requirements in 2019, but still requires that buildings be set back certain distances from property lines and leave set percentages of lots unoccupied by structures.

Market-minded housing affordability advocates, like the types who lined up to testify in support of HB 337 this week, say relaxing those sorts of rules would promote the construction of modest starter homes and duplexes in both existing neighborhoods and new subdivisions. Whether lawmakers buy that logic — and agree it’s worth preempting local planning control to implement it — remains to be seen.

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