Septic tanks are made from a variety of materials.
- Brick/concrete - Usually older tanks and of the 2 chamber design
It is vital to check that the tank does not leak, is not cracked or split and that the seals are intact. If not, then sewage can leak out in dry periods, contaminating public drinking water supplies. Groundwater can also leak during wet weather, flooding the soakaway. Many old brick and concrete tanks become porous with age and if over 30 years old, should be inspected very carefully when emptied.
Many newer fibreglass septic tanks only ever have a 12 month tank warranty. These should be inspected every year for cracks and the baffle should be tested to make sure that it is still attached to the wall of the tank.