MEMO
TO: Interested Public
FROM: Charles Shane, RS, Environmental Health Manager
DATE: June 25, 2025
RE: Proposed Changes to Missoula City-County Health Code, Regulation 1, “Wastewater Treatment and Disposal Systems”
On April 17, 2025, the Missoula City-County Health Board approved changes to Missoula City-County Health Code, Regulation 1, “Wastewater Treatment and Disposal Systems.” This change included adding an allowance for the installation of new wastewater systems to be installed in fill (artificially placed soil used to raise or level the ground surface). Before that change, only replacement systems could be installed in fill.
To allow this change in Missoula County, the Health Code had to be amended.
Before the new rules can go into effect, the Missoula City Council and Missoula County Commissioners must formally adopt them. These meetings include additional public comment opportunities:
Missoula Board of County Commissioners (Sophie Moiese Room, Courthouse Annex, 200 W Broadway)
First hearing and Initial Adoption Thursday, June 26 at 2 PM
Second hearing and Final Adoption Thursday, August 7 at 2 PM (Proposed)
The Commissioners meet in the Sophie Moiese Room
Courthouse Annex, 200 W. Broadway or
Remotely though Microsoft Teams
Missoula City Council
Public Safety and Health Committee Wednesday, June 25 at 4 PM
Public hearing and initial adoption Monday, August 11 at 6 PM (proposed)
Final Consideration Monday, August 25 at 6 PM (proposed)
The City Council meets in the Missoula City Council Chambers
140 W Pine St, Missoula or
Remotely through Microsoft Teams
Written Comments may be submitted through August 6, 2025 through
- Email: [email protected] or
- Mail: Missoula City-County Health Board, 301 W Alder, Missoula, MT 59802
Background:
Under a directive of the 2023 Montana Legislature, the Montana Department of Environmental Quality (DEQ) amended the statewide wastewater regulations to allow new wastewater systems to be installed in fill (artificially placed soil used to raise or level the ground surface). This change was incorporated into Circular DEQ 4, “Montana Standards for Subsurface Wastewater Treatment Standards.” Before that change, only replacement systems could be sited in fill.
Title 50, Chapter 2, MCA requires Health Boards to have wastewater regulations that are at least as stringent as the state’s rules. Missoula has had wastewater regulations since 1966, located in the Missoula City-County Health Code, Regulation 1 “Wastewater Treatment and Disposal Systems” (Health Code, Regulation 1).
To allow systems in fill in Missoula County, staff proposed changes to the Health Code Regulation 1. The proposed change strikes the section prohibiting the installation of drainfields in fill and relocates two parts of that section to the regulation addressing design, construction, location, and separation requirements.
To ensure safe and adequate treatment of wastewater, DEQ’s regulations (adopted by reference in the Health Code) require systems in fill to meet additional inspection, testing and compaction criteria. In addition, fill cannot be used to overcome horizontal or vertical setbacks and cannot be used in soil types likely to cause surfacing sewage (most clay and silts).
This update provides property owners and developers with more flexibility, particularly on smaller or previously disturbed lots where there is no viable alternative for a conventional drainfield. Since the revision of Circular DEQ 4, Missoula Public Health has received multiple requests to use fill for new systems.
For more information, please contact the Environmental Health Division at (406) 258-4755 or [email protected].