How to Install a Toilet in a Basement with a Rough-in Pipe

Wondering how to install a toilet in a basement with a rough-in pipe? Well, installing a toilet in the basement with a rough-in pipe isn’t a hard nut to crack if you have the necessary tools and know what to do.

It might seem difficult and expensive to add a flushable toilet in your basement bathroom, but it is an easy undertaking especially with the roughed-in pipes. Better still, the installation process should take a few hours even for a beginner.

What is a Rough-in Pipe?

A rough-in pipe is an unfinished plumbing pipe. The pipe is however ready for use but nothing is attached to it yet. For this reason, a rough-in drain is covered to prevent sewer fumes. The convenience dividends pay off with labor and minimal expenses, especially when the water and sewage systems are filled with rough-in.

Read on to find out how to install a toilet in a basement with a rough-in pipe.

Basic Elements of Water System

Before we get to know the tools, materials required, and how to install your basement bathroom, it is important to know the basic elements of the water system.

Sewer system

The basement wastewater system includes a sewer and drainage system that collect all the wastewater from different points in your home to water treatment sites. The drainage pipes are local city sewer systems that are connected either directly with municipal sewage treatment plants or rural sewage systems.

Water Supply and Distribution System

Water supply and distribution systems involve pipelines that carry different water from water sources to households and other different establishments. It also includes pipes supplying hot water from the boilers to taps.

Machinery and Equipment System

Machinery systems get gets wastewater from the equipment for treatment. Often, the machinery systems include a pump to get the wastewater, pipelines, sewage tank, sewerage purifier, sewage treatment systems, water leak detector, and sewerage pipe.

Ventilation System

Air is supplied to the drainage systems through the stove pipe. Although there are many reasons why heat does not pass through the roof, however, it may mean the air is not supplied to the whole structure. For this reason, a duct is created to fix the problem, but temporarily. The duct passes through the wall to connect to a ventilation tube in the loft.

How Do You Install a Toilet in a Basement with a Rough-in Pipe?

Tools Needed
  • Hacksaw
  • Hammer
  • Hand drill with drill bits
  • Pipe cutter
Materials Needed
  • Toilet
  • Toilet flange
  • Shut off valve
  • Concrete screws
  • Adhesive to match your rough-in material
  • Toilet supply hose

Steps to Follow Find the Rough-in Plumbing

The first thing to do is to locate the rough-in plumbing and this shouldn’t be difficult to find. Ideally, your rough-in will be located 12 to 14 inches from a wall. It often sticks out some distance from the basement floor and needs to be cut to size to allow for toilet installation.

Also, the supply pipes should be found nearby extending from the wall and ending about 9 inches above the floor. Ideally, the water supply pipe should be behind the drain and a little to the left side.

The flange may also be pre-installed and if it is, check its height. Since the rough-in piping is often installed before the house is finished, the flange may be left too high or too low. If it is too high, it means cutting it down and installing a new flange. You may need a flange extender if the flange is too low.

Prepare the Rough-in

Before you start preparing the rough-in for toilet installation, first shut off your water supply. Turn the supply to your home or if you can’t manage to turn it off, call the utility company to get it done.

If you intend to add other bathroom fixtures, you will require digging a trench to tie drainage lines into the toilet’s main drain line. Besides, you will require to tie into the water supply line, so if you intend to add extra bathroom fixtures, this is the time to consider doing it.

Install the Toilet Flange

Before installing your toilet, you must prepare the drain line. Here is how to prepare the drain line and install the flange:

Inspect your drain pipe

Get to know the kind of drain pipe you have. Is it PVC, ABS or metal? Depending on the material of your drainage pipes, you will have to match your toilet flange to it for perfect installation.

Saw the drain pipe

Saw the drain pipe down to the floor level if it is not yet there. However, if it is within the floor level, use a hammer to remove the cap and use a cloth rag to block the sewer fumes.

Line up the flange

Make about two of the four holes in the flange to be halfway from the wall to allow the toilet to be installed straight. Make sure the closet bolt holes are on the side where the toilet will be connected.

Drill the flange and floor

With the help of a hand drill, make holes in your new flange. Use the hammer drill to make holes in the floor.

Clean and prepare the drainpipe and toilet flange

Use the fine-grit sandpaper for deburring both sides and clean both ends with a rag.

Apply adhesive to both ends

Depending on the material, buy an adhesive recommended to fuse it. You may consider purchasing ABS cement or any other.

Insert the flange

Make sure the flange and the interior of the drain pipe are well coated with adhesive before inserting the flange. Use the concrete screws to affix the flange to the floor. Also, caulk around the flange.

Install the Shutoff Valve

Certainly, your new toilet will require a water supply fitting with a shutoff valve. Installing a shutoff valve isn’t difficult. You can follow the following easy steps:

Turn off your water supply

Turning off your water supply will allow you an easy time to install the shutoff valve without causing any mess from the following water.

Cut the end of the pipe

Leave enough space to allow convenient installation of the supply valve. Equally, deburr the end using your sandpaper or a deburring tool.

Place the compression nut

You can slide the compression nut into the pipe to as far back as possible.

Place the compression ring

Make sure you fit in the compression ring correctly over the end of the water supply pipe.

Attach the compression valve

You can do this by sliding it over the compression ring. Once it is well fitted, hold it in place with the compression nut.

Tighten the compression nut

Tighten the compression nut using two wrenches, one tightening the nut while the other holding the compression valve in place.

Test for leaks

Test the shutoff valve to ensure no leaks. you can do this by turning the compression valve off by turning it clockwise until it stops. Turn on the water supply and check for leaks.

Install the Toilet

Now it is time to install your toilet. It is advisable to have someone to help you lift and correctly position the toilet. but you can equally do it alone if you have to. The following are steps to follow:

Install the closet bolts

Install the closet bolts through the wide opening. Slide them slowly into their final position. However, if your toilet set came with plastic clips to hold the bolts in place, be sure to slide them now.

Install the flange seal

You can wax the flange seal. But if you are installing the toilet alone, then a wax-less seal would be ideal. This is because the basement toilet can be installed incorrectly minus ruining the seal.

Set the toilet tank on

When setting the tank, do it carefully and position it over the closet bolts. The weight of the tank is enough to press down to fit, so you don’t need to press too. Ideally, install the toilet bowl then the tank thereafter.

Screw the nuts onto the closet bolts

Make the nuts snug with a wrench and make sure not to overtighten. Overtightening may break your toilet bowl.

Install the tank if required

You should have two nuts and one seal. Install the nuts and snug them down with a wrench.

Connect the water supply

Connect the water supply with the shutoff valve and the refill valve at the bottom of the toilet tank.

Test for Leaks

Once you are done and everything is set. turn the water on and check for leaks.

Frequently Asked Questions

Will I need a special toilet in the basement?

Definitely, yes. Gravity toilets aren’t the most ideal type of toilet for basement installation but still, they are a good choice though. Gravity toilets work by discharging water from the tank into the bowl while gravity aids in pushing down the waste into the drain.

Is it possible to install my basement bathroom without rough-in plumbing?

Older homes often don’t have a rough finish. So, if your basement lacks the basic vents and gutters, you will have to add them before installing the bathroom. Depending on where your main drainage pipe is located in your house, you may require to install a special toilet with an increased flush power.

Can I install my basement bathroom without breaking the concrete?

Yes, you can install your bathroom in the basement without breaking the floor concrete or bathroom walls. For this reason, you must purchase a toilet with a high water level.

Saniflo system is the best toilet system for this kind of installation as it requires to be put on the concrete floor. This is unlike the standard basement showers that require you to drill a shower base and concrete in order to create a drain system.


Hopefully, by now, you have grasped one or two things on how to install a toilet in a basement with a rough-in pipe. However, before you embark on this project, you must plan it out and know your expectations as well as limitations. It can be a lot easier if you have a toilet that doesn’t require drilling the concrete floor.

But since you already have a rough-in piper, there is no need for a special toilet. You simply need to connect the toilet to the pipe. With the easy-to-follow steps above, we believe you can install your basement toilet without hiring a professional plumber to do it.

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