How To Finish A Basement Bathroom With Rough-In Plumbing

A basement bathroom will be a great addition to a basement. However, you have to set up crucial connections to finish the bathroom. With rough-in plumbing, you can easily add function and value to your basement. We have done the research to help you finish your basement bathroom.

If you are finishing your basement bathroom with existing rough-in plumbing, these are the steps to follow:

  1. Decide where you would place your toilets, tubs, sinks, and other bathroom fixtures.
  2. Determine the location of the rough-in stub-outs.
  3. Check the water, drain, and vent systems for possible leaks.
  4. Attach the chosen fixtures to the rough-in connections.
  5. Secure and adjust the fixtures if needed.

It is also important to check the rough-in connections when constructing and finishing your basement. By doing so, you can use the stub-outs and pipes without breaking the basement's concrete walls. Keep reading to learn more about finishing your basement bathroom.

Installation of pipes in a bathroom of an apartment interior during renovation works. Blue plastic drain pipe for used water. How To Finish A Basement Bathroom With Rough-In Plumbing

Finishing A Basement Bathroom With Rough-In Plumbing

If you are finishing the bathroom on your own or with a professional, you have to prepare the supplies needed.

Here is a list of common tools and materials you need to finish a basement bathroom:

  • Wrenches - You will need different types of wrenches to adjust varying pipe sizes and materials.
  • Draining tools - If you have to remove debris from clogged pipes, you can use a plunger or hand auger to allow water flow.
  • Hacksaw, pipe cutters, or shears - If you have to replace or cut some pipe, these tools would help.
  • Pipe glue - You can create a water-tight seal around the mouth of the pipes when attaching the fixtures.
  • Extra washers, bolts, nuts, and valves - If the existing rough-in has rusty or damaged parts, replacing them may be necessary.
  • Cleaning materials - You will need to make the area clean and dry before using the finished bathroom.

You also need to check the type of rough-in already in place in your basement. If the rough-in system is copper or PEX, there are special supplies to prepare.

To start, you have to create a plan on what you want to see in your basement bathroom. If you are doing this project alone, it will help to get to know the process.

Follow these steps when finishing the basement bathroom with rough-in plumbing:

1. Decide On Where To Place Bathroom Fixtures

You have to make a layout for your basement bathroom fixtures. Decide where you would place your toilets, tubs, sinks, and other fittings. Get the measurements, then mark the areas where you plan to install the chosen fixtures.

2. Locate The Stub-Outs

Existing rough-in plumbing has studs or stub-outs, which you can uncap and connect your fixtures. If the location is far from the planned layout, you can drill holes for necessary waterlines and vents.

3. Check Any Leaks

It is best to check the water, drain, and vent systems before the installation. There might be sections of the rough-in pipes that have holes where water and air can leak. You can also assess in this step if you need to replace rusty and damaged pipes.

4. Attach Bathroom Fixtures

Aside from the necessary fixtures, you have to attach the essential parts of toilets like stop valves and flanges. For your shower, you would need the shower base and sprayer heads. You also have to install the faucets for your sinks and tubs.

5. Secure And Adjust The Fixtures If Needed

Caulk, seal, and secure the fixtures after connecting with the rough-in. You can also do initial testing for the flow of air and water. Adjust the fixtures if there are loose or too tight connections.

The process will take several days and an extra workforce to complete the bathroom. Even so, you can create a basement bathroom that adds value and function to your home.

Pipes and water valves in the basement

Why Is Finishing A Basement Bathroom Important?

Even though you might use your basement bathroom less often, it should still have the complete fixtures and connections. The basement might become a space that sees a lot of activity, so it would be convenient to have a bathroom that you could easily access.

If you converted your basement as a space for recreation or rest, you don't have to go upstairs to do your personal necessities. Hence, a basement bathroom is an essential addition to your home.

Continue reading to get familiar with the steps and materials to finish the basement bathroom.

What Does Plumbing Rough-In Include?

Even if your contractor assembled the rough-in for your basement, it is also essential to know its parts. If you have problems with the bathroom's water or drainage lines, you can fix and locate where the issues arise.

The rough-in would include the following:

  • Hot and cold water supply line (with caps to cover the pipes)
  • Sewer or drainage line
  • Vents (for both air and gas)
  • Drain pipes and holes
  • Frames for bathtubs, sinks, and shower bases
  • Necessary supports for other bathroom fixtures in the plan

Contractors install fixtures like tubs and showers in the rough-in phase to get the correct placement. If there are adjustments, your contractor can modify the framing and walls to accommodate the size of the fixtures.

How Much Does Rough-In Plumbing In A Basement Cost?

Completing a basement bathroom is an expensive project. Rough-in plumbing for a basement would cost around $2,000 to $20,000. Your expense for the rough-in depends on the size, quality, labor costs, and fixtures you want to include in your bathroom.

The bulk of the costs depends on the type of pipe you plan to install. Listed below are the types of pipes and the respective prices:

  • Polybutylene & Lead - $2,500 to $15,000 for replacement
  • Copper - $5,000 to $20,000 or $2-5 per foot for a full repiping
  • PEX (XPE or XLPE) - $2,000 to 5,000 or $0.50 to $1 per foot

It will cost you $320-600 for the labors costs of installing the water supply lines. You will shed another $240-450 if you choose PEX supply lines for your bathroom fixtures. If there is a need to install a sewage ejector system, it costs $160-300.

Aside from the pipes, here are installation costs for other fixtures to include in your budget:

  • Faucet - $225 to $475
  • Sink - $300 to $5,500
  • Toilet - $350 to $3,500
  • Bathtub - $ 1,500 to $2,900
  • Shower - $1,500 to $3,500
  • Bidet - $500 to $2,750

The rough-in plumbing is just one aspect of completing a basement bathroom. From the flooring to the paint choices, each detail of the bathroom is part of the plan. The more high-end materials you select for the bathroom, the higher the cost.

Read more: What Color To Paint A Basement Bathroom? [And What Type Of Paint To Use!]

Water pipes made of polypropylene PEX in the wall

How Do You Test Rough-In Plumbing?

After you install the rough-in, the next step would be testing its function. You need to do drain, waste, and vent systems testing. According to the code, you will need to do water and air tests to check leakages in your pipes.

  • For the water test, fill at least 5 feet of water above the highest fitting connection of the completed system. Hold the water for at least 15 minutes. Check if there are any leaks in the connections.
  • For the air test, maintain a gauge pressure of 5 PSI for at least 15 minutes. Keep the vents closed so that no additional air can come in.

Ask your state building office if there are other testing requirements to meet. You can refer to this checklist to help you assess the rough-in processes to follow relevant building codes.

How Do You Install A Toilet In A Bathroom With Rough-In Pipe?

Installing a toilet in a basement bathroom is possible with rough-in connections in place. You can do the installation on your own or let a plumber do the work for you.

Here are the steps to install the toilet:

  1. Locate the rough-in drain pipe. Remove any cap or cover. Block the sewer fumes with a cloth.
  2. Check the height of the existing flanges. You need to cut if the flange is too high or add a flange extender if it is too short.
  3. Prepare the drain line for your toilet. Clean the drainpipe before attaching it to the flange.
  4. Afterward, attach the shut-off valve to the end of the water supply pipe.
  5. Install the toilet and its tank.
  6. Connect your water supply between the shut-off and fill valves on the bottom of the toilet tank.
  7. Check any leaks when testing the water supply.

polypropylene PEX in the wall, plumbing in the house. How To Finish A Basement Bathroom With Rough-In Plumbing

In Closing

A basement with rough-in plumbing makes finishing a bathroom easy. You only have to locate the stub-outs of the rough-in and connect the bathroom fixtures. Before any installation, be sure to prepare the necessary materials.

Due to the complex process of finishing, it is necessary to account for the costs. You also have to check if the rough-in works as expected. It is best to ask a professional when finishing the bathroom to avoid damage like leakage. With the rough-in, you can make the basement bathroom functional.

If you want to learn more about basement bathrooms, take a look at these posts:

What Is A Good Size For A Basement Bathroom?

Does A Basement Bathroom Need A Window


  1. Thanks guys a lot. This problem makes me headache. Now I can know useful information from your article to install a toilet with a rough in pipe.

  2. How to install a toilet in a basement with a rough in pipe? Installing a flushable toilet in a basement is not hard if you know what to do with the necessary tools. It might seem like adding a toilet to your crawl space is expensive, but it is an easy project if you have roughed-in pipes. The best part is that the installation usually only takes a few hours, even for a beginner.

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