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Connecting Tub Drain To Waste Pipe [Explained]

The drainage system in the bathtub must be perfectly set up in order for it to function smoothly. The tub drain does not come pre-connected to the waste pipe.

But connecting tub drain to waste pipe, is it really that hard?

No, connecting the tub drain to the waste pipe is not a tricky task. After gathering your tools, carefully set up the connecting pipes. Then, secure the pipe connections in both the tub overflow and drain. Finally, after tightening all of the screws and checking the installation, you can wrap it up.

This is merely the beginning. And we have the complete details of the procedure right here. Have some time on your hand then how about you take a quick look at it?

Sounds about right? Then we will get started.

How to Connect Tub Drain to Waste Pipe

The bathtub’s tub drain is connected to the waste pipe to empty the tub and prevent overflow. But the connection is not pre-assembled by the manufacturer.

Fortunately, the procedure is really simple. Anyone with a basic understanding of plumbing can connect the waste pipe to the tub drain. You may need to create a temporary shower while installing these connections.

But we’ve shown how to easily connect these two parts of the tub drainage system. It will help even a  DIY plumber to do it quickly. But before we go into the steps, we will look at what the drain kit consists of.

Mechanism of the Tub Drain

The tub drain kit is divided into two pieces. The drain basket and the overflow. The drain basket fits over the drain shoe.

The drain overflow connects to the drain shoe. You must properly connect the tub drain kit’s individual parts.

Only then will it go directly into the waste drain pipe. The waste pipe is then connected to the main sewage system.

Depending on the construction of your home, it may also be connected to the septic drain pipe. You can complete the task using simply a screwdriver, an adjustable wrench, and glue.

5 Steps for Connecting Tub Drain to Waste Pipe

By this time you’ve learned about the tub drain kit. We will now take a look at how you can connect the pipes. You will be needing the following equipment for the procedures:

  • T connector pipe
  • Overflow pipe
  • Drain shoe extension & drain basket
  • Slip nuts, cotter pin & spring clip
  • 2 Rubber gaskets
  • Crosshair
  • Stopper, Overflow Linkage
  • Screwdriver & pliers

After getting the essential tools and materials, you can start the installation. The following are the steps to connect the tub drain to the waste pipe:

Step 1: Attach the T Connector Pipe With the Overflow Pipe

At the top of the T connector pipe, you will find a big opening. The overflow pipe needs to be attached here. Insert the overflow pipe through this opening.

After that, take the drain shoe extension and connect it to the T connector with the slip nuts. The drain shoe securely fits into the T connector as it is angled at  90 degrees. 

At the bottom of the T connector, there’s also a non-extended pipe. You need to add this part with the drain pipe with the slip nuts.

Sometimes the pipes can be a bit longer than your measurements. You can simply cut the extra length with a small hacksaw.

Step 2: Secure the Pipe Connection

The rubber gasket is required to properly seal the drain shoe and the tub. It will be directly fitted on top of the drain shoe. The drain shoe must then be held just underneath the tub’s drain part.

Next, you need to attach the drain basket to the top of the tub drain. After that apply a small amount of silicone to the drain basket’s rim. Secure this connection to the tub by screwing it in place. There will be no leaks as a result of this.

The kit’s cross-hair must also be secured. Put a pair of pliers right through the cross-hair of the kit. It needs to go right through the drain basket. Turn the pliers set to secure the drain basket in its proper location.

Then fasten it with the attached drain shoe. Make sure not to overtighten the connection or the threads will be damaged.

Step 3: Secure Overflow Connection

You’ll need another rubber gasket for this connection. The rubber gasket must be inserted into the gap between the tub and the overflow pipe. It secures this connection.

It’s time to put the stopper in the overflow pipe. Connect the overflow cover linkage to the stopper. This connection can be made with a cotter pin or a spring clip.

To measure the overflow mark on the bathtub, the stopper must be properly plugged in. Otherwise, it will overflow and flood the bathroom floor.

After attaching the linkage to the stopper, you need to adjust it. You need to ensure the stopper fits perfectly into the drain hole.

Step 4: Tighten All the Screws and Slip Nuts

The overflow cap should be screwed into the overflow pipe. The cap and pipe flange will both have two screw holes. Tighten the screws properly with a screwdriver. You need to tighten the slip nuts after that.

Check to see if they’re as tight as possible without damaging the thread. Modern slip nuts are simple to tighten with just your hands.

But, for a proper tightening procedure, I recommend using a pair of pliers. It also ensures that the slip nut connection is leak-proof.

Step 5: Check The Installation

To keep water from draining, press the drain stopper to handle down. Fill the tub halfway with water and check the level.

Detach the overflow plate if the water drains significantly when the stopper is down. Then, remove the overflow pipe’s stopper and linkage. 

Lower the linkage just so the stopper is seated deeper in the drain. Replace the linkage in the overflow pipe and tighten the overflow cap. Press the stopper and start refilling the tub.

If the tub no longer drains, the stopper is properly installed. If it empties too quickly, raise the stopper. And lower the stopper if the tub empties slowly. This is a trial-and-error method that may need repeated adjustments until the stopper is properly seated.

After this, check to see if the overflow marking is properly installed. The stopper should open when the water level increases above the overflow indicator. This will allow the excess water to drain directly into the waste.

Can A Tub And Washing Machine Share the Same Drain

Similar to a water softener and a washing machine sharing a drain, the tub can share it too. Because just like the tub, washing machine drain pipes are also 2 inches.

You can connect the drains as long as you follow the 2-inch regulation. You can’t use a pipe larger than 2 inches since it won’t move the water adequately. It will result in a pool of water at the drainpipe’s bottom. 

Cost of Installing the Pipe

If you’re replacing an existing pipe, the process is rather simple. All of the pipes are ready and you may just require a few new pieces. This reduces the cost. On the other hand, additional costs will be added for new installation.

Also, the plumber needs access underneath the tub and where the overflow pipe attaches. If these areas are hidden, the plumber has to cut access panels into the floor and wall.

These will raise the price because you will need to do tiling around the floor drain again.

The approximate cost of materials for a bathtub drain installation is $96.35. But it can range anywhere from $86.44 to $106.26.

Your total cost will be determined by your task size, selection of fittings, and working circumstances. You can use these products for better fittings and durability:

Product 1
Product 2
Product 3


Is a P-trap required in a bathtub?

Yes, a P-trap should always be included in the pipework of a bathtub. Failure to add a P-trap could result in bad odors and toxic gases. And without a p trap, small animals can easily crawl into the tub through the tub drain.

What are the differences between a P-trap and an S-trap?

The horizontal length of the pipe that permits you to connect the vent is the only difference. An S-trap can be converted to a P-trap by attaching a vent to a pipe. They should be 4 inches long at the very least.

Is there a limit to how far a drain may be extended without a vent?

If you’re using a 1- 1/4-inch pipe, the vent’s horizontal distance shouldn’t exceed 30 inches. The vent for a 1-1/2-inch pipe must be within 42 inches. And for a 2-inch pipeline, 5 feet distance will be enough.

What is the size of the bath waste pipe?

Bath waste pipes are usually 40 mm. Cisterns and cold water tanks use 21.5mm pipes. The hand basin on the other hand uses a 32mm waste pipe.

End Words

By this time, you know all about connecting tub drain to waste pipe. I hope the instructions were easy enough for you to understand.

If it’s still too difficult for you don’t hesitate to contact a plumber. It might be a bit costly but they will get your tub drain all set up in no time.

Until next time. Good Day!