MT HB658

Removes local boards of health authority to adopt sanitation-related rules more stringent than state standards for sewage control/disposal and sanitation in public/private buildings

Grandfathers existing subsurface onsite wastewater treatment systems (septic systems) that are installed and functioning, exempting them from future local rule changes unless the system shows signs of failure

Requires local boards of health to provide landowners written documentation of all requirements for new septic system installations and any subsequent rule changes, with clear evidence for any additional requirements

Allows secondary components of septic systems to be used without additional approval if the primary component fails, provided the system was originally installed with backup components

Takes effect immediately upon passage with retroactive applicability to all septic systems installed before the effective date