cost to replace septic system
1 The average septic system replacement cost ranges from $6,000 to $50,000 including financing. 2  Up to 50% of the replacement septic system cost is profit for the installer, therefore our solution is rarely mentioned.3  Most regulators are risk averse and avoid breakthrough technology.nderstanding Septic System Repair Costs. 1  The average septic system replacement cost ranges from $6,000 to $50,000 including financing. 2  Up to 50% of the replacement septic system cost is profit for the installer, therefore our solution is rarely mentioned.