Basement Sewage Flooding


Basement flooding can occur anytime. It can happen to anyone who has a basement even if the basement has never flooded before. While most flooding occurs during heavy rain, the worst type of flooding is caused by sewage backup. This must be addresses quickly as sewage backup carries lots of bacteria and will create a smell and may make your family sick.


  • When it rains heavily the sewage system often becomes filled with more waste and water than it can carry. When this happens the sewage and water needs to find somewhere to go. It will find its way into your basement.
  • If you have a private septic system you may get backup when your septic tank is filled and needs to be cleaned out, or if your drain lines to the septic needs to be cleaned.
  • If you have recently added a bathroom to your home, and your drain lines are not large enough for the extra sewage, you will get backup in your basement.


  • The best way to prevent sewage backup is to install a backwater valve in your basement. This valve is located in the floor with a cover. When the sewage tries to come up rather than going down, the flap inside the valve will automatically close off the opening so sewage cannot enter your home.
  • If you have a valve and still experience sewage backup, you probably need to clean out the valve. This needs to be done regularly to ensure the flap can freely close.
  • Ensure that your shut off valve is inspected at least once per year. You can hire a professional to come and inspect your basement drainage system or you can do it yourself. Your local plumber will come out and show you the process you need to follow when inspecting.

If you have a basement, you can expect that sooner or later you will experience some type of drain backup. Knowing what to expect and how to correct the problem quickly will aid you in prevent sewage flooding in the future.