Sanitation Act and Local Wastewater Treatment System

Application Processes

In preparation for what will be another busy building season, we have implemented changes to our process with the intention of providing services that continue to be efficient and complete. To better serve you and provide staff with the time necessary to complete reviews of submitted applications, please note the following important changes:

Walk-in Hours:

  • Mondays 1 pm to 5 pm
  • Thursdays 8 am to 12 pm (noon)

By appointment:        Please call the office at (406) 582-3120 to schedule a time.

We ask that you provide as much of the following information as possible at the time you schedule the appointment so staff can prepare for the meeting.

  • Have you had discussions regarding this project with GCCHD staff? Who?
  • Is this project related to Sanitation Review or a Local Wastewater Treatment System?
  • What is your basic question(s)?
  • Property Owner
  • Property Information: COS, Existing Wastewater Treatment System – Permit #Tract / Lot
  • Minor Subdivision #
  • Existing COSA – EQ # (if you don’t know you can obtain this information in the Gallatin County Clerk & Recorder office, click here for a list of questions to ask)
  • Site Address

Please contact the department at (406) 582-3120 if you have any questions.

Wastewater (Septic) Treatment

Our goal at the Gallatin City-County Health Department is to protect human health and the environment through proper treatment and disposal practices in Gallatin County. The department achieves this through education, individual registration, inspections, and a system for reporting and resolving problems.

Click here to learn more about wastewater systems


Important Requirements

• A local wastewater treatment system permit is ALWAYS required before a system (non-public or public) is installed.

• Site evaluations must be performed by a Gallatin County Registered Site Evaluator or a Professional Engineer registered in the state of Montana.

• A Gallatin County Registered Installer must be on-site during the installation of every system.


Types of Wastewater Treatment Systems

Non-public Wastewater Treatment Systems

Environmental Health Services is responsible for ensuring that non-public wastewater treatment systems (individual/shared, multi-user) are permitted and installed in accordance with state and local regulations. Proper placement, type, and sizing of systems are based on either a Certificate of Subdivision Approval (COSA) or a site evaluation which assesses the site to determine if suitable conditions exist for on-site wastewater treatment and dispersal.

Public Wastewater Treatment Systems

Montana Department of Environmental Quality (MDEQ) has primary responsibility for public wastewater treatment systems, which are defined as serving more than 24 persons for more than 60 days a year or having more than 14 connections.

Septic Pumpers

Septic pumpers are required to obtain a license from MDEQ. Their equipment and disposal sites are regulated to ensure proper treatment of waste.



Gallatin City-County Environmental Health Map

Forms & Applications


Wastewater Treatment (Septic) Records

Financial Assistance Options for Installation of New and Replacement Sanitary and Wastewater Systems


Contact Gallatin City-County Health Department (GCCHD) for more information: (406) 582-3120 or