Conventional Septic System Cost in New Hampshire
Estimated 2026 installed range: $4,300 – $9,800
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Open the cost calculatorWhy New Hampshire prices differ
Statewide cost drivers here are freeze depth, bedrock and older housing stock. Locally, bedrock and slope are the dominant cost factors. That is why a conventional system in New Hampshire can land well above or below the national range of $3,500–$8,000.
All system types in New Hampshire
| System | Low | High |
|---|---|---|
| Conventional | $4,300 | $9,800 |
| Chamber | $6,100 | $13,400 |
| Aerobic / ATU | $9,800 | $22,000 |
| Mound | $12,200 | $26,800 |
| Sand filter | $9,800 | $19,500 |
What conventional systems are for
A conventional system uses a tank plus a gravel or pipe drain field. It needs deep, well-drained soil and adequate space, which is why it is the cheapest option when the site allows it.
Related pages
All septic costs in New Hampshire · Conventional system overview