Aerobic / ATU Septic System Cost in Illinois
Estimated 2026 installed range: $8,200 – $18,400
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Statewide cost drivers here are clay soils and deep frost. Locally, county health departments enforce strict setback distances. That is why a aerobic / atu system in Illinois can land well above or below the national range of $8,000–$18,000.
All system types in Illinois
| System | Low | High |
|---|---|---|
| Conventional | $3,600 | $8,200 |
| Chamber | $5,100 | $11,200 |
| Aerobic / ATU | $8,200 | $18,400 |
| Mound | $10,200 | $22,400 |
| Sand filter | $8,200 | $16,300 |
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.
Related pages
All septic costs in Illinois · Aerobic / ATU system overview