Mound Septic System Cost in Delaware
Estimated 2026 installed range: $10,800 – $23,800
Get your own estimate in 30 seconds
Open the cost calculatorWhy Delaware prices differ
Statewide cost drivers here are high water tables and clay soils. Locally, flat, wet lots frequently need mounded systems. That is why a mound system in Delaware can land well above or below the national range of $10,000–$22,000.
All system types in Delaware
| System | Low | High |
|---|---|---|
| Conventional | $3,800 | $8,600 |
| Chamber | $5,400 | $11,900 |
| Aerobic / ATU | $8,600 | $19,400 |
| Mound | $10,800 | $23,800 |
| Sand filter | $8,600 | $17,300 |
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.