MT HB180

Local boards of health are prohibited from adopting regulations that allow subsurface wastewater treatment system mixing zones to encroach onto adjacent property for parcels created after March 30, 2011

Drainfield mixing zones approved before March 30, 2011 under the Sanitation in Subdivisions Act, or approved before October 1, 2025 under local health board authority, are exempt from the encroachment prohibition

Well drilling regulations must prohibit wells if the well isolation zone (100-foot radius around a water well) encroaches onto adjacent private property without the property owner's authorization

Amends Sections 50-2-116 and 76-4-102 of the Montana Code Annotated to revise the definition of "proposed drainfield mixing zone" and clarify local board of health authority