septic tank installation cost
1 According to estimates from the EPA (that are about 10 years old), the septic tank installation cost, including the tank and drain field, can cost anywhere between $1,900 and $9,000 with an average of $4,000 for a standard system in an area with good soil. As for the tank itself, the cost of this should also be considered. 2  A rough guideline is between $1 and $4 per gallon of tank, so a 1000 gallon tank installed would cost between $1,000 and $4,000.