An Introduction to the Septic Tank

Septic tanks are common in rural areas, but they may be used in suburban areas, especially in older homes that haven’t been connected to the sewer main. We’ll explain what septic tanks are, how they work and how they are maintained. 

What is a septic tank?

A septic tank is a tank that is buried in the ground. It may be made of concrete, fiberglass or plastic. Wastewater from the nearest building is sent to the septic tank. It separates out solids from liquids, breaking the solids down somewhat. The liquids are then sent down pipes to seep into the soil of a drainage field. This allows for the sanitary disposal of solid and liquid wastes from a property when there isn’t a sewer line to use for this purpose. 

How do septic tanks work? 

When the solids and liquids from the household hit the septic tank, heavier material separates and sinks to the bottom of tank. This is by design. Anaerobic bacteria attack the solids, turning some of them into gas and others into liquids that can pass through the pipes exiting the septic tank. The term septic comes from this class of bacteria. The somewhat treated wastewater flows out of the pipes into a disposal field. This will seep into the soil in an area chosen for this purpose. This wastewater will not contaminate groundwater or drinking water unless the septic tank floods or the drainage field improperly drains into the nearest body of water. 

What type of maintenance do septic tanks work? 

The bacteria break down some of the fecal and waste mater, but the rate is never as fast as matter is added to the septic tank. Septic tanks will eventually fill with solid mass. This means they need to be pumped out periodically. Depending on how much wastewater you use and how often you send indigestible solids into the septic tank, you may have to pump it out every three to five years. 

If you send sanitary napkins, massive wads of toilet paper or other large items down the drain, this can clog the pipes to the septic tank or the drainage field pipes. That will cause back flow regardless of how much material is in the septic tank. Regular pumping out of the septic tank will also prevent solid mass or sludge from the septic tank from clogging the drain field pipes. 

It is rarely necessary to add new bacteria to the septic tank unless it has just been pumped. You never need to add water to the septic tank. You’ll know that the septic tank needs to be emptied of solids when there is unusually lush growth in the drainage field, the wastewater pipes in your home are slow to drain, you’re hearing gurgling as pipes are drained or there are wet spots in the yard. If you smell or see waste in the drainage field, this could indicate a blockage or just a break in the drainage pipes. Rich plant growth in one particular part of the drainage field is another indication. 

This is why you want to have septic tanks inspected once a year. Keep records so you don’t let it sit too long without being inspected or pumped.