Septic System Cost in Connecticut
Estimated 2026 installation range: $4,600 – $10,400 for a conventional system.
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Open the cost calculatorTypical costs in Connecticut
| System | Low | High |
|---|---|---|
| Conventional | $4,600 | $10,400 |
| Chamber | $6,500 | $14,300 |
| Aerobic / ATU | $10,400 | $23,400 |
| Mound | $13,000 | $28,600 |
| Sand filter | $10,400 | $20,800 |
What drives cost in Connecticut
Statewide, the biggest factors are freeze depth, bedrock and older housing stock. Locally, older homes often need full replacement plus Title V compliance upgrades. Permits and site work often account for 20–30% of the total.
Choosing the right system for your lot
Start with a soil test. If the soil is deep and well drained, a conventional system is usually the cheapest choice. If the water table is high or the lot is tight, expect a mound or aerobic system and a higher budget.
Next step
Use the calculator to get a range with a line-item breakdown for your bedroom count and site conditions, then compare with at least two licensed local quotes.