There are two major factors involved in adding a new system or repairing or replacing an existing one. The first is the cost; the second is the inconvenience of possibly not being able to use the existing system while a replacement is being installed. For new construction, the second factor is not usually a major consideration.
Repair or replacement cost will obviously depend on what has to be repaired and/or replaced. If the repair does not involve the leach field, the cost may be high, but it will probably not be exorbitant. The least expensive repair will be associated with a broken pipe between the distribution box and the house. The cost for this type of repair is in the order of several hundred dollars. If only a septic tank needs to be replaced – and the leach field is still undamaged – the cost will be in the order of about $1500 to $2500. If a new leach field is needed, and there is room for such an installation, you should plan on spending an additional $2000 to $3000 for a typical home. If there is not sufficient room for a new leach field, the existing field, including the clogged soil, must be removed and a completely new system must be installed. Such an effort can easily exceed $10,000.