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Discharge Line

A discharge line is an important piece in your basement waterproofing puzzle as it enables the sump pump to move water out.

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When homeowners talk about their basement waterproofing, they can be quick to praise the sump pump and forget the discharge line. This piece of the sump pump transports water out of the basement to the outside, playing a key role in protecting homes from floods. Without it, a sump pump cannot function properly. 

Let’s take a closer look at what a discharge line is, how it is installed, and what you can do to protect this attachment in the freezing weather in Colorado. 

The best way to prevent your exterior discharge line from freezing is to have the FreezeGuard™ installed. One of our specialists will install it on the outside end of your discharge line to protect it from backups. Even if the discharge line freezes up, water will still be able to drain and escape through the FreezeGuard™ attachment

What Is a Discharge Line? 

A discharge line is a 1½-inch PVC pipe that connects to your sump pump and takes water out of the basement. It usually goes through the basement wall and discharges water a safe distance away from the home’s foundation. 

Discharge Line Installation 

Once your waterproofing contractor sets the sump pump up in its basin, they will proceed with discharge line installation. Here’s how a typical installation goes: 

  • The short length of the pipe is connected to the check valve’s end. 
  • A 45- or 90-degree PVC elbow is glued to the short pipe to route the piping towards the foundation wall. 
  • Another pipe is added followed by an elbow at the wall. 
  • A vertical pipe is installed from the elbow to the rim joist above your foundation wall. 
  • A hole is drilled through the rim joist and the exterior siding to route the pipe. 
  • The piping continues with a 90-degree elbow and a horizontal pipe that goes through the rim joist hole. 
  • Once outside, the pipe is routed back down 5 inches below the frost line and out to your preferred discharge point so water flows away. 
  • Finally, the hole around the rim joist is sealed with caulk. 

Make sure the grade slopes away from your house. To prevent backflows into the sump basin, ensure the contractor installs a check valve inside the discharge line. 

Discharge Line Protection 

During winter, the exterior discharge line can freeze and block water from being pumped out of the basement. This happens when layers of ice form and freeze shut the 1½-inch opening. The sump pump will still be able to run but won’t discharge water. 

As water pressure builds up inside the pipe, the pump’s motor will start to strain while trying to eject water that’s collecting behind the clogged area. The resulting stress will weaken the PVC joints, causing the pipe to leak or burst. Eventually, the sump pump’s motor will overheat and burn out. The result is water will flood your basement. 

Insulating your discharge line and the intake part of the pipe is a good defense against freezing. One way to do this is by wrapping the pipe with heat tape. Avoid using automotive antifreeze. 

As we mentioned, another thing you’d want to do is ensure the discharge line has a positive grade and is flowing away from your home. What this does is prevent standing water, which tends to trickle back or freeze in cold weather. 

Your discharge line’s performance determines how the sump pump will function and how long it will last. Try to perform maintenance on this line twice a year. Some contractors will let the discharge line dump water right next to your home. That’s not good. The best way to set up a discharge line is to bury it underground and to direct it far away from your home. This way, water won’t recirculate back to your basement. 

As part of your basement waterproofing, Complete Basement Systems can help you install and maintain your sump pump and discharge line. We’ll also install the FreezeGuard™ to ensure water doesn’t back up inside the pipes and damage your motor. Contact us to request a free waterproofing inspection and repair quote