Septic System Information

A permit is required for all septic systems or waste water treatment systems installed in Madison County. All waste water systems shall be installed by a Madison County Licensed Installer.

Lots Over 20 Acres & Lots Created Prior to the Subdivision Law


To obtain a septic permit for lots over 20 acres and lots smaller than 20 acres created prior to the subdivision law, the following must be submitted to our office:

Instructions for Part C


  • Soils Profile - An 8-foot test hole will need to be dug, using a backhoe, to determine the possible groundwater level and to obtain a suitable Soils Profile.
  • Water Sample Results - The Results from a Nitrates and Specific Conductance test on the well water must be submitted. The water will need to be taken from the existing well, or if a well has not been installed it can be taken from the nearest well to the property. Contact our office for water sample bottle.

Lots Under 20 Acres With Deq Approval


State of Montana Environmental Quality:
To obtain a septic permit for lots less than 20 acres created after the subdivision law the following must be submitted to our office:

Additional Resources