A Guide on Doing Rough-In Bathroom Plumbing

The bathroom has a lot of plumbing including water supply lines and drains. Showers, sinks, toilets, and tubs drain their water into one main sewer line.


These bathroom fixtures are fed with cold and hot water supply lines that branch toward the bathroom fixtures. Rough-in bathroom plumbing involves preparing the pipes and drain lines for connection once a bathroom fixture is put in place.

This process is usually done when setting up a new bathroom. It requires some specialized tools and plumbing skills to get it right.

rough in bathroom plumbing


Here’s how to go about it:


Step 1

First, create a map that will represent the rough-in layout for your bathroom. Next, locate the closest drain stack. Draw the path that the drain and water supply lines will take to get to the bathroom.

Also, draw the location where the pipes will be installed in the bathroom. When drawing the layout, consider where the bath or shower, sink, and toilet will be located.

Use a pencil to sketch the bathroom and the pipe network, including the pipe sizes for every branch.


Step 2

Once you’ve created the map for the rough-in layout, get a pipe T-connector and install it to the sewer stack. The T-connector will create a branch drainage that will carry the wastewater from the sink, toilet, and tub or shower to the main sewer line.

You’ll need a big pipe cutter for opening the main stack. Take a 3-inches pipe T-connector (PVC) and insert it to the opening you made on the stack. The connection point for the connector should be made at the bathroom’s floor level.

This will allow for water to drain downhill toward the connector. Use cement and PVC cleaner as per the instructions of the manufacturer when installing the pipe.


Step 3

Now run a 3-inch diameter pipe (PVC) to the location of the toilet drainage. Make a turn of 90 degrees upward such that it will reach a level below the floor. Next, connect each pipe with two female adapters.

Use cement that is specially made for use with PVC pipes when making the connections. Use another elbow (90 degrees) to make the pipe turn horizontal again. Split the pipe with a pipe splitter to get two pipes.


Step 4

Take a pipe measuring 3-inch in diameter and install it into one of the split pipes. Next, fit in a 3 to 2 inches adapter onto the other pipe. Next, run a pipe measuring 2 inches in diameter to where the sink will be located.

Turn the pipe upward using an angle of 90 degrees. Next, install a pipe measuring 2 inches in diameter and allow it to run above the floor to a height of 18 inches. This pipe will work as the drain for your bathroom sink.


Step 5

Next, split a 3-inch diameter pipe in half. Take an elbow (90 degrees) to join the split pipes such that one length will go upward to where the toilet will be install.

Next, install a flange for your toilet. The flange should be installed above the floor surface. At this point, the drainage is fully ready for toilet installation.


Step 6

Take a 3-inch diameter pipe and run it to the tub or shower drain location. Use an elbow (90 degrees) to make it turn upward. Take another 3-inch diameter pipe and run it to the floor level to serve as the tub or shower drain.


Related Articles:

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Fixing A Whirlpool Bathtub Without A Plumbing Access Panel

A DIY Guide On How To Remove The Bathtub Drain

The Basics of Sink Plumbing in the Bathroom

How to Repair Your Leaking Bathtub

By |2020-03-29T23:59:33+10:30November 16th, 2019|DIY Plumbing|0 Comments

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