Informational Guide

How To Plumb A Shower Drain

We show you how to plumb a shower drain like a professional plumber. Follow our simple step-by-step guide with pictures & diagrams.

by Josh Mitchell

A clogged shower drain is not only annoying but can lead to water damage, pipe damage, and major plumbing issues if not taken care of promptly.  

If you have a clogged shower drain, it is imperative that you take care of it quickly. We put together this article to talk about DIY shower drain plumbing.  

As expected, shower drains remove water from your shower or shower/bathtub combo. As the water flows down the drain, it forms a vacuum that might slow the flow of water. As such, shower drains are vented so water can flow freely. Hari and other debris from showers can clog up the drain and prevent water from flowing.  


Parts of the Shower Drainage System 

  • Drain Trap
    The drain trap is a U-shaped part of the pipes that allows a small amount of standing water when the drain is not active. The standing water keeps sewer gases from coming out of the pipes. 
  • Vent
    When water flows into the drain, it creates a vacuum that can affect water flow. All shower drains have a vent to the outside to provide air, so no vacuum forms. 
  • Drain Body And Parts
    The drain body is the main pipe that sits below the visible drain grate that connects the drain to the rest of your plumbing system. The drain body is usually made from PVC, ABS, or cast iron. 
  • Drainage Seal And Shower Base
    The drainage seal goes around the drain strainer and makes sure that water does not leak out of the base and damage your floor. The base is slightly angled down to keep soapy water from forming a slippery film on the bottom of the shower. 

Things to Consider When Installing a Shower Drain 

Here are some important things to keep in mind when installing your shower drain.  

  • Pipe Size
    If the drain body is not the same size as the rest of your plumbing system, then you will not be able to connect. The result is that your drain can leak water out of the base and damage your floor. 
  • The Cut Through The Ceiling
    If your drain is located on the second floor, then you may have to cut through the ceiling from the bottom to get at it if it is too far down. You do not need to cut through the ceiling if you are replacing the drain and shower base. 
  • Trouble With Tight Spots
    Make sure that you have a clear plan of where pipes need to go. One problem many people run into is that they do not have enough space to arrange their pipes and drains. Drain systems that have a lot of curves are more likely to get clogged. 
  • Consider Replacing The Whole Trap
    If your drain keeps clogging, then you might need to replace the drain trap. Over time, drain traps can get clogged and break down. They can also crack and start leaking. Fortunately, replacing a drain trap is pretty simple.  
  • Weep Hole Blockages
    Weep holes are small open spaces that let moisture dissipate from behind tiles. Weep holes prevent water from being trapped behind your tiles and forming mold. Weep holes can be blocked from fallen mortar and other building materials. 

How to Plumb Your Shower Drain (Step-By-Step Instructions) 

  • Wrench 
  • Hacksaw or tubing cutter 
  • Pliers 
  • Plumbers putty or caulk 
  • Power drill 
  • Tile trowel 
  • Pipes and fittings 

1. Plumbing a shower drain on Tile 

How To Plumb A Shower Drain
  1. 1
    First, you need to make sure the subfloor is prepared and cleaned. Install the bottom flange of the drain in the other pipe and glue it into place with solvent glue.
  2. 2
    Next, use the trowel and spread mortar, making sure there is a ¼ inch dip for every foot. You want the floor to slightly slope to the drain away from the walls.
  3. 3
    Next, install the middle flange by bolting it to the bottom flange. Check the liner for leaks by pouring water over the shower pan.
  4. 4
    Arrange the tiles around the drainpipe, taking care to leave a small gap for grouting the drain grate.
  5. 5
    Position the tiles on mortar and press them into place.
  6. 6
    Next, slowly twist the shower drain counterclockwise or clockwise to raise or lower it until it is flush with the tile line.  

2. Plumbing a shower pan drain 

How To Plumb A Shower Drain Diagram
  1. 1
    First, test fit the shower pan over the hole and draw a line on the edge of the subfloor for reference purposes.
  2. 2
    Next, cut a circular hole in the subfloor for the drain pipe and drain fitting. 
  3. 3
    Now you need to prepare the subfloor with mortar. Make sure the mortar is flat and evenly spaced.
  4. 4
    Make sure the drain body is fit with the shower pan and install the drain body into the bottom of the shower pan.  Seal the drain body in place using silicone caulk.
  5. 5
    Place the rubber sealant washer and cardboard friction washer on the underside of the shower pan.
  6. 6
    Next, place the shower pan so that the drain body fits over the drain pipe. Make sure the shower base adheres to the floor. 
  7. 7
    Next, place the drain pipe gasket over the opening and tighten until the drain body and pipe are tightly connected. 
  8. 8
    Snap the shower drain screen into place and check your work for leaks.

3. Plumbing a Bathtub Shower Drain 

How To Plumb A Tub Shower Drain
  1. 1
    First, you need to remove the old stopper. You should be able to rotate the stopper and pull it up out of the flange.  
  2. 2
    If you have a lift-and-turn drain, loosen the center screw that holds the stopper in place.
  3. 3
    Using pliers, grip and unscrew the exposed drain flange to remove it from the bottom of the tub. Scrape off any residue or putty with a plumbers knife. 
  4. 4
    Add a new layer of plumbers putty around the rim of the flange and screw it back in tight using the wrench. Don’t over-screw the new flange. 
  5. 5
    Next, install the new or old stopper. The way the stopper will connect depends on the kind of drain that you have. 
  6. 6
    Lastly, add some water and test whether the new drain leaks. Pur in water and let it sit for around an hour.  

4. Plumbing a Shower Drain in the Basement 

  1. 1
    If you have a concrete floor in your basement, then you will first have to break open the concrete and dig a trench so you can reach the pipe. The trench needs to be wide enough to attach the drain pipe and drain trap.
  2. 2
    Once you have the concrete broken up and the main drain pipe exposed, attach the drain trap to the drain pipe. 
  3. 3
    Next, you need to refill the concrete around the pipe. Make sure to leave space to install the shower base and drain grate.
  4. 4
    Next, attach the drain body through the shower base and place the base on the concrete, so the drain body goes into the drain pipe. 
  5. 5
    Insert the gasket into the drain flange and screw it into place.
  6. 6
    Next, attach the drain grate and test the shower setup for leaks.  

If you do not wish to do this job yourself then we recommend getting a local plumber to do the job. You can find free quotes from your area by filling in the form below.


How to Plumb Shower Drains to Avoid Sewer Gases 

Sewer gases are constantly trying to work their way through your shower pipes to escape in your home. The drain trap is the main mechanism that keeps sewer gases from leaking back into your home.  

The U-shaped bend keeps a layer of standing water as a barrier to sewer gases. The drain trap can get clogged and prevent your shower from draining. If this happens, you need to remove the drain trap and clear it out.

The most common thing that clogs drain traps is hair. You can mostly remove any blockages by pushing a wire coat hanger through the drain trap.  


People also Ask (FAQs)

Does a shower drain need a trap? 

Yes, shower drains need traps because they keep sewer gas from backing up into your home.  

Why does a shower require a 2 inch drain? 

2 inch pipes have a low threshold for flooding and drain faster than smaller pipes.  

What is the proper pitch for a shower drain? 

Shower slope should be about 4%, or about a ½ inch drop for every 12 inches horizontally.  

Do you glue a shower drain? 

Yes, you can glue your shower drain grate to the pipes.  

What should you do to clean and maintain a shower drain? 

Drains should be flushed with a mixture of vinegar, baking soda, and water periodically. You also need to regularly remove and clean the drain trap 

How far can the P trap be from the shower drain? 

The max distance the P trap can be from the drain is 24 inches. 

Should shower drains be grouted in? 

You can grout them in, but caulk is probably the better idea as it won’t clog the drain.  


Conclusion

Shower drains need to be planned in advance and should not be left to the end. Maintaining your drainage system will reduce the risk of leaks and plumbing damage.  

Josh enjoys researching, testing and diving into home improvement & DIY products. He has a passion for tools, learning new skills and fixing the everyday problems that arise around the house.

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