Understanding the Parts of Your Septic System

If your home uses a septic system, it helps to know what’s going on underground. While the system is designed to run quietly in the background, understanding its parts can help you take better care of it — and catch problems early.

Here’s a simple breakdown of the main parts of a typical septic system and what each one does.

The septic tank

This is the main holding tank where all the wastewater from your home goes. It’s usually buried underground, close to the house. The tank separates solids, grease, and liquids into layers:

• Sludge sinks to the bottom
• Scum (toilet paper, grease) floats to the top
• Effluent (liquid) stays in the middle and flows out to the next part of the system

Bacteria in the tank help break down some solids, but the rest builds up over time and must be pumped out every few years.

The baffles

Baffles are located at the inlet and outlet of your septic tank. Their job is to direct the flow of wastewater and keep solids from exiting the tank too early. If baffles are damaged or missing, it can lead to drainfield problems or backups.

The drainfield (leach field)

Once the liquid leaves the tank, it flows through a series of perforated pipes into the drainfield. This is typically a section of your yard with trenches filled with gravel and soil. The soil filters the wastewater naturally as it absorbs into the ground.

A healthy drainfield is key to preventing backups and protecting groundwater.

The inspection ports or risers

Modern septic systems often have risers — round plastic or concrete pipes that extend to the surface to give easy access to the tank lids. These make inspections and pumping much easier (and cleaner).

If your system doesn’t have risers, a technician may need to dig to access the tank.

The distribution box (if installed)

Some systems have a distribution box that helps evenly spread the wastewater across the different trenches of your drainfield. Not all systems have one, but if yours does, it should be inspected occasionally to make sure it's not clogged or sinking.

Bottom line

A septic system has a few key parts, and they all need to work together to do the job right. Knowing what’s underground can help you understand the importance of regular maintenance and make informed decisions about your system.