You should call a licensed installer for a quote if you already have your plans.
The installation cost of a septic system can vary widely depending on the site and soil conditions, the installer, and the type of drainfield that is installed. These ranges are only a guide for you to compare relative costs of the different types of systems commonly installed.
On average you can expect to pay $4,000-$6,000 for a conventional septic system, $6,500-$8,500 for a conventional septic system that requires a pump, $10,000-$15,000 for an alternative septic system that requires pretreatment into conventional drainfield lines, and $20,000-$24,000 for an alternative septic system that requires pretreatment into drip irrigation.
Contact SETEC (540 381-0309) for recommended installers.