MT SB532

Counties with zoning regulations must allow at least one accessory dwelling unit (ADU) by right on any lot with a single-family dwelling, with no public hearing, variance, or conditional use permit required

Counties are prohibited from requiring owner-occupancy, matching exterior design, impact fees, additional parking, or imposing more restrictive building standards on ADUs than on the primary dwelling

Counties may charge a one-time application fee of up to $250 per ADU, in addition to standard building fees

The Department of Environmental Quality must provide a 15-day expedited sanitation review for ADUs added to parcels with existing public water and wastewater service that has capacity

The expedited review provisions terminate September 30, 2029