Flathead Lakers Public Comment on FC Septic Pressurized Regulations 2026.docx
March 4, 2026
Dear Mayor Hunter and Members of the Kalispell City Council,
Thank you for providing an opportunity for public discussion regarding the recent changes
to Flathead City-County Health Department septic system regulations.
Onsite wastewater systems play an important role in protecting the water quality of our
lakes, rivers, and groundwater. Flathead County’s shallow aquifer system and its
documented hydraulic connectivity to surface waters make wastewater management
decisions particularly important in our region.
For more than two decades, Flathead County has required pressure-dosed septic systems
rather than gravity distribution systems. This policy was adopted in the early 2000s in
response to growing development pressures and concerns regarding nutrient loading and
groundwater transport pathways.
Pressure distribution systems are widely recognized as providing a more even distribution
of wastewater throughout the drainfield, reducing the risk of localized overloading of soils
and improving the overall performance of the soil treatment system. These systems are
especially important in areas with shallow groundwater, variable soils, or proximity to
surface waters, conditions that exist in many parts of Flathead County.
At the same time, we recognize that gravity systems can perform adequately when installed
in locations with suitable soils, slopes, sufficient unsaturated soil thickness below the
drainfield and distance to groundwater, appropriate setbacks from surface waters, and
slopes that allow proper hydraulic design. For some rural property owners, gravity systems
may also be more affordable and easier to maintain because they do not require pumps or
electrical components.
Given these considerations, we encourage the City and County to consider a balanced,
risk-based approach.
Rather than eliminating the pressurized system requirement entirely, we encourage the
county to retain the pressure distribution as the default standard while establishing a clear
variance process for gravity systems where site conditions demonstrate equivalent
protection of groundwater and surface waters.
PO Box 70 | 110 Main St., Suite B | Polson, Montana 59860
Tel. 406-883-1346 | www.flatheadlakers.org
Such a process should require careful evaluation of:
• Soil texture and percolation characteristics
• Thickness of unsaturated soil below the proposed trench bottom
• Depth to the highest seasonal groundwater table, with a minimum of eight (8) feet of
vertical separation from ground surface to seasonal high groundwater - or equivalent
unsaturated soil thickness - in areas underlain by coarse glacial outwash or otherwise
identified as hydrogeologically vulnerable
• Proximity and hydraulic connectivity to surface waters
• Ground slope and site drainage characteristics
• Cumulative density of onsite systems within the contributing area
In Flathead County’s glacial outwash soils, where groundwater movement can be relatively
rapid and hydraulically connected to surface waters, enhanced vertical separation provides
increased travel time and additional treatment opportunity before effluent reaches the
aquifer. Requiring greater separation in these sensitive settings is consistent with a
precautionary, risk-based approach to protecting water quality.
This approach would:
• Maintain the precautionary protections that have guided wastewater management in
Flathead County for the past two decades, considering hydrogeologic vulnerability identified
in regional groundwater assessments.
• Allow flexibility for rural property owners where site conditions demonstrably support
conventional gravity design.
• Ensure that water quality protections are based on measurable site characteristics rather
than uniform relaxation of standards.
Flathead County’s lakes, rivers, and groundwater are among our region’s most valuable
assets. Wastewater policy should reflect both sound engineering principles and the specific
hydrogeologic realities of our region. Thoughtful wastewater policies are essential to
ensuring that growth occurs responsibly to protect these invaluable resources for present
and future generations
Thank you for your consideration.
Coby Gierke
PO Box 70 | 110 Main St., Suite B | Polson, Montana 59860
Tel. 406-883-1346 | www.flatheadlakers.org
Executive Director
The Flathead Lakers
PO Box 70 | 110 Main St., Suite B | Polson, Montana 59860
Tel. 406-883-1346 | www.flatheadlakers.org