How Your Septic Tank Works

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how your septic tank works

Understanding how your septic tank works will help you increase its longevity, save money, and take better care of your home’s plumbing. If you know enough to notice when something’s wrong with your tank, then you’ll be able to have it fixed before it becomes a real problem.

Of course, all this is easy for us to say. We have a lot of experience with ins-and-outs of septic tanks. Getting to know your septic tank can be intimidating. It might even sound gross! We get that, which is why we put together this primer. Here’s what every homeowner should know about their septic tank:

What is a septic tank?

A septic tank treats wastewater through natural biological decomposition and drainage processes. They’re usually made of concrete, fiberglass, or polyethylene. These large, rectangular or cylindrical tanks collect all the wastewater that comes from your home’s sewer line.

Septic tanks have two pipes connected to them on each end. Waste water from your home’s sewer line enters the tank via the inlet pipe. Waste water sits in the tank long enough for solid waste materials to separate from the water. Then, the outlet pipe pumps the processed wastewater out of the tank and spreads it throughout the drain field. The waste inside the tank separates into three individual layers: oil, liquid, solid.

What do septic tanks do?

All the waste in your home flows into the septic tank. The tank repeatedly takes in and fills with watery waste. While this water sits in the tank, anaerobic bacteria break down and separate out the waste inside it.

These bacteria separate the waste in the tank into three categories. “Sludge”, or solid waste, separate out to the bottom of the tank. Sludge is made mostly of inorganic solids and byproducts of bacterial digestion. “Scum” (made up of fats, oil, and grease) floats to the top of the tank. The middle layer is all the water that’s left over after bacteria separates the sludge and scum out. The tank works like a settling pond. It separates and then redistributes leftover waste evenly in the surrounding drainfield. The drainfield naturally absorbs water into the soil, where it’s harmless or even beneficial.

How do I maintain my septic tank?

There are two main ways to maintain your septic tank: regular pumping and protective maintenance. It’s smart to get your septic tank pumped every three to five years. If your tank is small or sees heavy use, you may even want to pump it more often. A professional plumber will clear out the sludge, scum, and leftover water in the tank. When the tank is clean, new and healthy bacteria will begin to form inside it.

Tree roots often very seriously damage or even rupture septic tanks when they collide with the tank underground. You should carefully maintain the trees and plant life around your septic tank to ensure its safety. Keep the area around your tank clear, and make sure your drain field is level and absorbent.


If you ever need help with your septic tank, call the professional plumbers at The Pink Plumber today. We can fix your problem and teach you how your tank operates at the same time. The more you know, the more you’ll save!

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