Aerobic / ATU Septic System Cost in Montana
Estimated 2026 installed range: $8,000 – $18,000
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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 aerobic / atu system in Montana can land well above or below the national range of $8,000–$18,000.
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 aerobic / atu systems are for
Aerobic treatment units add oxygen to break down waste faster. They are used on tight or wet lots, require electricity, and need periodic maintenance.