How long does a septic system last?

The lifespan of a septic system depends on the material it is made of, the design, installation, service and exposure conditions, and maintenance of the system. Typically, a septic tank made of concrete may last 40 years or more, although older tanks may not be as well constructed as newer tanks. Tanks made from other materials, such as plastic may last a similar timeframe.

If your septic system includes a pump, many pumps and controls will need to be replaced every 6-12 years. If you have an advanced treatment unit, check with the manufacturer for estimates of lifespan and warranty information.

If your drainfield is more than 25 to 30 years old, the natural biomat that forms in the bottom of the trenches or beds can thicken and reduce the ability of the drainfield to properly discharge the wastewater into the ground. This can cause ponding in the drainfield, surfacing of untreated wastewater, or backing up into the septic tank and into the plumbing in the house.

If your septic system is more than 25 to 30 years old, start planning for an upgrade before you are in an emergency situation. It is likely your system is close to its useful lifespan.