cost to replace main line to septic
1 However, if the project is complex and/or if the connection to the public system is in the middle of the street it can cost $7,000-$25,000 or more. 2  CostHelper readers report paying $4,500-$13,000, or $50-$100 per foot traditional replacement of 50'-100' of sewer line, for an average cost of $7,493 or $106 per foot.