Question: how much does it cost to put in a new septic system?
Answer: Septic System Replacement Cost The cost of septic system replacement depends on the type of system installed. Here are the average ranges: Gravity fed drainfields of all types: $5,000 to $10,000, or an average of $7,500. Mounds: $10,000 to $50,000, or an average of $30,000.