What to Know About Your Basement Floor Drain

Why You Need a Floor Drain

A floor drain is essential for allowing water to escape from the basement. Here are some of the main reasons you need one:

  • Prevents flooding – Any water leaking through walls or the foundation can drain away rather than pool in your basement. This prevents extensive water damage.
  • Allows draining of appliances – Things like water heaters, sinks, washing machines, etc. need a floor drain to empty waste water.
  • Drains during cleaning – It gives you a place to drain excess water when mopping floors or using a hose to wash things down.
  • Limits moisture – It helps reduce humidity and dampness that can cause mold and mildew growth.

Having at least one floor drain in the lowest part of the basement is crucial for any finished or unfinished basement.

Locating the Floor Drain

The floor drain is usually installed in the lowest spot of the basement. This allows gravity to pull all water towards it. Here are some common locations:

  • Near the water heater and utility sink
  • Front corner by foundation walls
  • Back corner by foundation walls
  • Next to washing machine hookups

Newer homes often have plumbing roughed in for a future bathroom, with the floor drain placed by the toilet site.

If you can’t locate the drain, check the basement floor carefully for a covered opening. Old drains may be obscured by debris or flooring.

Inspecting and Maintaining the Drain

It’s important to periodically inspect your basement floor drain and keep it maintained. Here’s what you need to do:

  • Remove any debris like leaves or dirt that may clog the drain opening.
  • Flush it out monthly by pouring a few buckets of water into the drain.
  • Use a drain auger or plumbing snake to remove any stubborn clogs.
  • Make sure the drain cover is clear and securely fitted.
  • Check that the drain line is sloped properly to empty into the main home drain line.
  • Have a plumber inspect the drain pipe condition every few years using a drain camera.
  • Install a backflow valve if you experience sewer gasses coming from the drain.

Neglecting the basement floor drain can result in clogged pipes, flooding damage, and excess moisture issues.

Signs of Problems

Watch for these signs that may indicate an issue with your basement floor drain:

  • Standing water around the drain, instead of emptying.
  • A mildew smell coming from the drain.
  • Gurgling sounds as water goes down.
  • Slow draining of water into the drain.
  • Sewer gas odors coming from the drain.
  • Visible cracks in the drain pipe.

If you notice any of these, it likely indicates a clogged drain, broken pipe, or other problem needing professional repair.

Finishing the Basement Around the Drain

Many homeowners finish their basement to add living space. The floor drain must be handled properly when putting in basement flooring:

  • Leave the drain accessible – don’t cover it completely with flooring.
  • Install a drain cover that fits flush with the finished floor.
  • Cut flooring around the drain opening.
  • Attach a removable access panel if installing a ceiling below.
  • Leave room for any drain maintenance needs.
  • Direct all flooring slightly towards the drain.

With careful planning, you can integrate the floor drain into a finished basement. This retains its important drainage capabilities.

Converting an Unused Drain

For older homes with an unused floor drain, it’s best to replace it with a functioning drain:

  • Confirm it’s not connected to any pipes before capping it off.
  • Use an expanding rubber cap or hydraulic cement to plug the old drain.
  • Install a new drain connected to the main home drainage pipes.
  • A qualified plumber can determine the best new location and do the installation.

Never leave an unused drain open, as dangerous sewer gasses can enter the home. Replacing it improves basement drainage.

Installation of a New Floor Drain

Homes lacking a basement floor drain should have one installed:

  • A plumber can determine the optimal drain location and pipe routing.
  • The drain line needs a proper slope to empty into the main home drainage line or septic tank.
  • A PVC drain pipe is fitted and glued leading to the disposal point.
  • The drain cover and opening are installed flush with the floor.
  • Water appliances are routed to empty into the new drain.

Adding a floor drain provides critical protection against water damage in basements prone to flooding.

What to Know About Your Basement Floor Drain

Having a properly functioning floor drain is one of the best ways to protect your basement from water damage. By understanding its purpose, inspecting it routinely, keeping it maintained, and handling it properly during basement finishing, you can keep this critical drainage system working properly. Your basement will stay dry and free of flooding with a well-installed floor drain.

Frequently Asked Questions About Basement Floor Drains

What size is a standard basement floor drain?

Most basement floor drains are 3-4 inches in diameter and connect to a standard 2-inch or 3-inch PVC drainage pipe. Larger 4-6 inch drains may be used for high-capacity needs.

How can I clean out my basement floor drain?

Use a drain snake or auger to remove debris, flush with hot water, or use caustic chemical drain cleaners to dissolve organic clogs. Avoid harsh chemicals with a metal drain.

Why does my basement drain smell bad?

Sewer gases escaping from the drain can cause foul odors. Try flushing with bleach water or replacing the drain trap. If that doesn’t work, have your drain pipe professionally cleaned.

Can I cover my basement floor drain?

You can install a removable cover flush with the floor, but never seal it completely. This allows access for cleaning and maintains proper drainage.

How much does it cost to install a basement floor drain?

If piping is in place, just installing the drain itself ranges $200-500. Fully routing new piping and an drain can cost $2000 or more. Get estimates from local plumbers.

Should a laundry room have a floor drain?

Yes, a laundry room should always have a floor drain located near the washing machine. This prevents overflow and spills from causing water damage.

What should I do with an unused old drain in my basement?

Unused drains should be properly capped or plugged, as they allow sewer gases to enter if left open. Replacing with a functional new drain is recommended.


A properly installed and maintained basement floor drain is one of the best preventative measures against expensive water damage and flooding. Inspecting your existing drain routinely, keeping it clear, handling it correctly when finishing basement floors, and installing a new one if needed will help keep your basement dry for years to come. With a little regular care, your basement floor drain can save you from dealing with extensive repairs down the road.