Septic Tank Replacement

While concrete septic tanks are said to have a 50 year life and are preferred over plastic tanks for their durability and strength, we experience the phenomenon of corrosion in a few instances, which results in a softening of the concrete and eventual collapse of the tank.  The corrosion occurs at the outlet end of the tank and affects the top of the tank around the access lid, as well as the outlet end wall.  As the corrosion progresses, the edge of the access lid opening softens and the lid falls into the tank.  In the worst case, the entire 4” thickness of the tank wall softens and a rod can be pushed through into the dirt; the entire outlet top of the tank can collapse into the tank, along with the dirt on top.  If the tank is located near the house, safety dictates replacing the tank. 

Our charge for replacing tanks is about $2,500.00 - $3,000.00, plus a health department repair permit costing $250.00, obtained by the property owner.  Please see Health Departments under Resources.  The process involves backhoe excavating a hole in the ground for the new tank; placing of the tank; pump-out, demolishing and backfilling the old tank; re-routing and connecting the sewer line inflow from the building and outflow to the field; a health department inspection; and recovering of the tank and placement of risers and lids to grade for easy access. It takes 2 days and does not interrupt the usage of the system.

We need to verify whether any utilities exist in the area, such as water and gas mains and sub-mains, electrical, telephone and cable, and sprinkler irrigation systems.  We are responsible to repair any damage to known and located utilities; the property owner is responsible for repair and replacement of any finish landscaping and sprinkler system components damaged.

We will compact the backfill around and over the tank, and leave the soil mounded to allow for 10%-15% settling over time.  Usually, there is no excess soil left over, as the backfilling of the old tank consumes the soil excavated for the volume of the new tank.  However, disposal of any excess soil needs to be addressed, whether it is wasted on site or hauled away.