Everything You Need To Know About Rough-in Your Plumbing

A good home requires good plumbing. Therefore, a properly prepared sketch of the plumbing system, known as “rough-in plumbing,” is required for your home plumbing installation. The goal of a rough plumbing schematic is to create a permanent and unchangeable plumbing installation foundation. The advantage of rough-in plumbing is that once you have a general idea of where your plumbing pipes will go, you can move forward with construction and plumbing installations without worrying about the pipelines because you’ll know exactly where they’ll go.

How to Install Plumbing Rough-in

You’ll need the assistance of a professional plumbing firm or individual plumbers for appropriate plumbing installation. But some towns allow homeowners to install their plumbing systems. So if you have an idea and expertise in plumbing, then you can go ahead and submit your rough-in plumbing draft. To make the process easier for you, we have made a step-by-step guide for roughing in your plumbing.

Step 1. Pinpoint Important Locations 

Bathrooms are one of those places that involve the most plumbing installations. The layout of toilet plumbing should be immaculate because poor toilet plumbing can not only ruin your plumbing system but also ruins the look of your home. The first step is to mark all the locations where your toilet will be and mark its center on the wall. Next, measure out 13 and a half inches from that central point for the bathroom flange. Finally, place the actual flange on that marked point and trace a line outside of the flange ring. 

Step 2. Cut Out the Drain Hole

Now it is time to cut out your drain hole and fix in it your bathroom flange. First, cut out the section you previously marked and place the flange in the hole formed with two extended slots on each side. Now screw the flange to the bathroom floor and use shims if required. 

Step 3. Installation of Drain Pipe 

Installation of drain pipes happens beneath the floor called subfloor. It is because, during roughing-in work, actual floors are not installed, so the drains can be placed under the floor without any problem. ‘Waste stack,’ the main wastewater pipe is used, the drain is directed towards it with a 3-inch long, 90-degree turn fitting, running it into a 3-inch by 3-inch by 2-inch Y-shaped fitting. Y fitting is positioned in such a way that a 2-inch opening can be connected to the main vent pipe. 

Step 4. Installation of Supply Line

The next stage in roughing in your plumbing is to run a supply line up via the floor and wall, exiting near the water tank outlet in the bathroom. Attach an 8-inch section of the supply line and a screw-on cap fitting to the part of the “T” that will supply the toilet to prevent “water hammer.”

Essential Tips For Successfully Roughing in Your Plumbing 

Now that you have an idea about how you can perform a rough-in of your plumbing installation, we have some tips and tricks in store for you. By following these tips, you can avoid any mishap that might happen during rough-in. 

1. Be Prepared for Your Client’s Requirements

It is crucial to understand your client’s needs and requirements. The last thing you want is your client to be disappointed in you because you did not listen properly. You should always specify to your client what components you require and what methods you opt for. Check that you have all of the product specifications, layouts, and drawings that the customer demands before you begin. A tour around the framed house might also be beneficial. This will allow you to double-check the proposed placements for fittings and piping to ensure they match the blueprints.

2. Prioritize Your Work Accordingly 

If you are doing the plumbing for a whole building, you should prioritize your work accordingly. You should start from the bathroom. The reasoning is simple, as this is the area that requires the most plumbing and the most specialized plumbing as well, such as waste lines, water faucets, etc.

3. Keep Tabs on Your Local Competitors

The simplest way to ensure that your rough-in plumbing is charged accurately for the location’s demands is to mean out the competitors’ prices. Though, if you provide extra assistance not included in the standard package, you can justify higher pricing.

4. Make Sure to Run the Final Water Test

It is important to ensure that nothing is amiss after everything has been installed. The best way is to run the water test. The method is to run water according to the blueprint and install the water shut off. Check if there are any leaks. You should also call for an inspector for their opinion. 

5. Use Gravity with the Waste System

As an air pressure system is absent in the water system, gravity is used. This is done by gradually lowering all the pipelines at the rate of 1⁄4 of an inch per horizontal foot.


Your home plumbing is the most crucial step for your construction, so it should be done professionally. Our guide helps you to understand the process of rough-in plumbing better. 

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