Is Basement Floor Drain Connected To Sewer?

The basement floor drain is a vital plumbing feature in a finished basement. If you're in doubt about the connections of the drains and pipes and whether or not the floor drain is connected to the sewer, you're on the right page. We've consulted the experts, and here's what they have to say.

For most residences, the basement floor drains connect to the sewer system. This connection will help drain water from the laundry sinks and washing machine. Also, the link to the sewer system prevents bad odors inside the basement. However, a common problem with the connection is sewage water backflow.

The pathway connecting the floor drain and sewer is crucial to avoid plumbing problems. Without proper maintenance, you can create more problems for the sewer line. It will also help to refer to local codes to avoid environmental violations. Keep reading to learn more about basement floor drains.

A plumber checking the basement floor drain, Is Basement Floor Drain Connected To Sewer?

Why Are Basement Floor Drains Important?

The main job of a floor drain is to remove excess and unwanted water in the basement. You will find the drain under a sloped concrete floor in the utility area. The drain collects water on the floor and discharges it to the main sewer line or a sump pit. A floor drain is essential if you use the following fixtures:

  • Humidifier
  • HVAC unit
  • Sinks
  • Showers
  • Toilets
  • Washing machine
  • Water heater

A basement floor drain can also reduce water damage in times of flooding and heavy rains. It will help you remove any accumulated water inside the basement. But then, you should also maintain the drain to keep it working.

Where Does A Basement Floor Drain Lead To?

Innovations in construction can have intricate plumbing linkages. The connections should have a route that allows the free flow of water while it separates from the sewer line. There are relevant residential codes to follow as a precaution against environmental violations.

An opened floor drain in the floor

But you might as well first be aware of the common connections of the basement floor drain as we have outlined below:

1. Sewer System

The floor drains connect to the main sewer line for most homes. It is a large 4-inch pipe that runs from your home to the street to meet the city sewer lines. This connection is suitable for draining water from laundry sinks, water softeners, or washing machines.

To avoid foul odors from the sewer, you must not lose the plug for the cleanout. Also, the trap under the drain should not remain dry.

2. Sump Pit

Another option is to connect the floor drains to a sump pit. It consists of a hole and a gravel base in the lowest part of a basement. The water collected activates a sump pump when it reaches a certain level. Afterward, the pump discharges the water out of the house through the pipes.

The connection can violate your local ordinances if you connect the drain to a sump pit. The water drained through this line can have chemicals, detergents, salts, and other waste that can harm the environment.

3. Sump Pit With Ejector Pump

Adding an ejector pump to the sump pit is helpful if the basement floor drain is lower than the main sewage lines. The ejector pump directs the waste to the sewer system. This type of connection is suitable when you drain from sinks and washing machines.

Read more from this post: Can I Drain Basement Dehumidifier To Sump Pump [And How To]

Do Basement Floor Drains Have P-Traps?

All plumbing fixtures have traps. A basement floor drain has a u-shaped trap under the floor drain called a P-trap. The left side of the P-trap connects to the drain, and the other side connects to the sewer line. The gas accumulates at the bottom of the trap to prevent the sewer gases and insects from entering the basement.

You can only see the grill or cover grate of the P-trap, and all other parts are under the basement floor. Some brands offer P-traps with a cleanout or a backflow valve.

Click here to see this P-trap on Amazon.

To maintain its condition, you should always fill the trap with water. The trap will dry fast around 3-5 months or even as early as one month. When the water seal of the P-trap dries, sewer gas can fill the basement. You can avoid this issue by pouring a pitcher of water into the drain every two weeks.

Why Does My Floor Drain Keep Backing Up?

You will see "standing" water in your basement floor drains more often because it is the lowest drain in your home. The water from the higher levels of the house will run down and find its way to the floor drain.

Water leak in the basement floor due to faulty floor drain

If water backs up from the floor drain, there is clogging in the sewer pipeline. The sewer lines are prone to damage like cracks, holes, and sagging. There can be an obstruction in the way of the water inside the pipes. When this happens, sewage water can back up and goes back to the drain.

Other causes of the floor drain backing up include:

  • Broken connection to the main drain line
  • Deteriorated sewer pipe
  • Flat spot or dip in the drain line
  • Faulty sump pump
  • Improper and abusive flushing
  • Tree root growth

Check out a related post: Basement Sink Backing Up – What To Do?

If you do not solve the issues, you might get in trouble when there is flooding in the basement.

How To Stop Basement Floor Drain Backing Up

Here are the steps to unclog the basement floor drain and stop the backflow.

  1. Remove the pooling water on the surface of the basement floor.
  2. Then open the cover grate of the floor drain to access the drainpipe.
  3. Check the catch bowl if there is debris. Scoop and dispose of the waste properly.
  4. Use a drain snake to clear the drainpipe.

If you want to save on labor costs, you can clean the floor drain yourself. You can use materials like a plunger, baking soda with vinegar, or hot water to clean the drain.

One long-lasting solution is installing a backflow check valve. The valve has a flapper that only allows water to flow in one direction. You can install one near the main sewage cleanout. To operate the valve, you can choose a manual or automatic option.

Click here to see this check valve on Amazon.

To prevent clogging, you should regularly clean the drain and pipes every 3 months. If the issue is severe, a sewer line repair or replacement is necessary. It is best to ask a professional to fix it if you don't have the expertise and tools for cleaning or repairs.

White PVC connected to the basement floor drain

Learn more from this other post on How To Unclog A Basement Drain.

In Closing

A plumber checking the basement floor drain

A basement floor drain will connect to the sewer system. When water accumulates at the drain, it will discharge through pipes leading to the main sewer lines. It also has a P-trap that keeps foul odors from the sewer from coming into the basement.

But then, you should also prepare for floor drain backups. The water from the sewage system can cause water backflow to the floor drain. You can avoid the issue by cleaning the clogged drain pipes. If you maintain your pipes, traps, and drains, a connection to the sewage system is not a problem.

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