Septic Tank Backup

Quick Summary

For many people in rural areas, septic tanks are a way of life. Normally, they’re out of sight and out of mind. That’s until something goes wrong and the septic tank backs up. Then there’s a problem and a nasty mess. There’s also the question of what to do. If your septic tank does back up, here are steps you can take to fix the issue.

How a Septic Tank Works

The first thing in dealing with a septic problem is to understand how a septic tank actually works. There are three parts to a septic system:

  1. There are lines or pipes running from your toilet, sink and tub that work through gravity to carry waste outside to the tank.
  2. The holding tank acts as a bacterial chamber that breaks down solids.
  3. There’s the disposal field that distributes liquids to be absorbed into the ground. A blockage or obstruction in any one of these sections will cause a septic backup.

Types of Septic Tanks

There are three main types of septic tank materials. One is concrete, the second is fiberglass and the third type is manufactured from polycarbonate. Their difference is in the range in price and their strength or durability. All perform the same job of holding waste and separating solids from liquid but their materials have no bearing on backup.

What makes a difference in septic tank backups, is the overall type of septic tank “system” you have. There are two different types of septic systems. One is simple and works on gravity draining your waste out to the tank. When the septic tank reaches an overflow capacity, gravity then drains the liquid out to the disposal field.

The second septic system is more complex because it’s pressurized. Gravity still takes waste from the house to the main tank where solids separate and settle on the bottom. The overflowing liquid is then gravity-fed to a second smaller tank downstream. But here, there’s a pump that pressurizes the overflow liquid and blows it evenly out over the drain field.

Steps to Take When Fixing a Septic Tank

Now that you know how septic systems work and what type you have, you need to diagnose the problem and take these steps to fix it.

  1. Isolate the blockage. Start with opening the tank lid and checking the content level. If the tank is low, you have an upstream blockage between the house and the tank. If the tank is full, you’ll have a downstream problem.
  2. Check for an interruption of power or a stuck float switch. Usually, restoring either will get your system up and running.
  3. Call in a professional who has the knowledge and tools to externally remove the blockage. That includes cameras to find the exact cause and location as well as augers to clear the obstruction.

Septic Tank Backup Prevention

The most important step you can take is to prevent a septic tank backup in the first place. Here are some preventive suggestions:

  • Make sure your septic tank is always biologically active. Don’t use antibacterial soaps and cleaners that drain to the tank.
  • Never put garbage or any foreign objects into the system. Human waste is biologically active by nature but raw food scraps are not. Garburators are terrible offenders.
  • Avoid planting trees anywhere near your septic lines. Tree roots are notorious for seeking water and nutrients inside sewer lines. They’ll puncture and block pipes in no time.
  • Do not run heavy machinery over sewer lines. Lines are easily crushed and destroyed.

A little prevention will go a long way in letting your septic tank operate indefinitely with little or no maintenance. That’s what it’s designed to do.

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3 References
  1. wikiHow. (2022) How to Unclog Your Septic Tank. Retrieved from:
  2. Sanco Industries. (2011) Septic Backups. Retrieved from:
  3. Anta Plumbing. (2015) 2 Main Causes of Septic System Backups. Retrieved from:
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