How much does septic system installation cost?
A new septic system's price depends on the type your soil allows — conventional gravity systems are cheapest, engineered/mound systems for poor soil cost multiples more. The perc test decides which you need.
| Typical range | $3,500 – $20,000 |
| Most common | $7,000 |
| Priced | conventional system |
| DIY-friendly? | No — best left to a licensed pro |
What changes the price of septic system installation
- System type — conventional vs. mound/engineered
- Soil conditions (perc test results)
- Tank size and material
- Permits, design and excavation
Estimate your cost
Adjust the quality and scope, or compare with other projects.
Full typical range for this project. Adjust the quality/scope for a tighter estimate. The only way to know your real price is to get quotes from local contractors.
- ›System type — conventional vs. mound/engineered
- ›Soil conditions (perc test results)
- ›Tank size and material
- ›Permits, design and excavation
National ballpark ranges for the US. Not a quote — actual prices vary by region, home and contractor.
Septic system installation cost — frequently asked questions
How much does a septic system cost?
A conventional septic system runs about $3,500–$20,000 installed, around $7,000 typical. Engineered or mound systems for poor-draining soil commonly run $15,000–$30,000+.
Related project costs
This is general US cost information, not a quote. Actual prices depend on your region, home, materials and contractor — always get quotes from licensed local pros before you commit.