Mound Septic System Cost in Montana
Estimated 2026 installed range: $10,000 – $22,000
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Open the cost calculatorWhy Montana prices differ
Statewide cost drivers here are hard ground, terrain and remote access. Locally, remote sites and short construction seasons raise labor costs. That is why a mound system in Montana can land well above or below the national range of $10,000–$22,000.
All system types in Montana
| System | Low | High |
|---|---|---|
| Conventional | $3,500 | $8,000 |
| Chamber | $5,000 | $11,000 |
| Aerobic / ATU | $8,000 | $18,000 |
| Mound | $10,000 | $22,000 |
| Sand filter | $8,000 | $16,000 |
What mound systems are for
A mound system raises the drain field above the ground when the water table is high or soil is shallow. It is one of the most expensive common options.