How to Install a Floor Drain in an Existing Garage

If you’re looking to add a floor drain to your garage, there are a few things you’ll need to consider. This is a relatively easy task that can be completed in a few hours. Here are the steps you need to take to install a floor drain in your garage. 

How to Install a Floor Drain in an Existing Garage

In this blog post, we’ll go over how to install a floor drain in an existing garage, including what supplies you’ll need and how to position the drain properly. You can rest assured that your new floor drain will be installed correctly and efficiently by following these steps. Read on for more information!

Summary: Installing a floor drain in an existing garage is a project that can be completed in a few steps. The first step is to choose the location for the drain and mark it on the garage floor. Next, the concrete around the marked area should be removed, and the subfloor should be prepared. A drain assembly should then be installed and connected to the existing plumbing.

Different Types of Floor Drains in Existing Garage

1. Cast Iron Floor Drain with Round or Square Top:

This type of floor drain is usually the most common and can be found in both new and existing garages. It features a round or square top with a cast iron body. The grate at the top can be removed for easy cleaning.

2. Cast Iron Floor Drain with Trap:

This floor drain also has a cast iron body, but it features a built-in trap to prevent sewer gases from entering the garage. The trap must be filled with water at all times to work properly.

3. PVC Floor Drain with Trap:

PVC floor drains with traps are commonly used in residential applications such as laundry rooms, utility rooms, and garages. These floor drains are easy to install and can be found at most hardware stores.

4. Stainless Steel Floor Drain:

Stainless steel floor drains are more durable than PVC drains and are often used in commercial applications. However, they are also more expensive. If you are looking for a long-lasting floor drain, a stainless steel model may be the best option.

Stainless Steel Floor Drains

5. Rubbermaid Floor Drain:

This is a great product for those who want to install a floor drain in their garage but don’t want to go through the hassle of concrete work. The product comes with everything you need for installation, and it’s extremely easy to use. Attach the flange to the drainpipe, seal the joint with silicone, and then set the drain in place.

6. Linear Shower Drain:

A linear shower drain is a type of floor drain installed in a straight line. This type of drain is often used in showers with stone or ceramic tile floors. Linear shower drains are available in various materials, including stainless steel, PVC, and cast iron.

7. Trench Garage Floor Drains:

A trench drain is a great option if you have a lot of water or debris on your garage floor. They are installed in a trench in the floor and can be either covered or open. The most important thing to consider when choosing a trench drain is the size of the opening. Also, make sure to choose one that will be able to catch all the water and debris that comes into your garage.

8. Square Bell Trap Drains:

There are square bell trap drains that can be installed in an existing garage. The installation procedure is similar to installing a floor drain in a new garage, with a few exceptions. First, the square bell trap drain must be glued to the garage floor using a waterproof adhesive.

Square Bell Trap Drains

Second, the drain pipe leading from the square bell trap drain must be attached to the main sewer line using a coupling. Finally, once the square bell trap drain is installed, it is important to test it periodically to ensure that it is functioning properly.

Choosing the Appropriate Floor Drain

There are a few factors you need to consider when selecting a floor drain for your garage:

1. Drain location:

It would help if you determined where the drain would be located in your garage. The most common location is in the center of the garage, but you may also choose to put it near a wall or in another area.

2. Size and Shape:

Floor drains come in various sizes and shapes, so you need to choose one that will fit the dimensions of your garage. If you’re not sure what size or shape to get, ask a salesperson at the store or measure the drain opening in your garage.

Floor Drains  Come in Various Sizes

3. Materials:

You’ll need a few materials to install a floor drain in your garage, including a drain grate, a PVC pipe, and a drain catch basin. You may also need some silicone caulk and concrete sealer, depending on the state of your garage floor.

4. The Drain System:

Most floor drains rely on a gravity-based drainage system. The water will flow down the drain pipe and into the sewer or septic tank. However, some floor drains have a pump system that helps move the water away from the garage. If you’re not sure which type of drain you need, ask a salesperson at the store.

5. Building Regulations:

When installing a floor drain in an existing garage, certain building regulations must be adhered to. The most important is ensuring that the drain is installed at least 2 feet below the garage floor. This is to ensure that any water that does enter the garage will be able to flow freely out and away from the structure.

6. Capacity:

The capacity of a floor drain is important to consider, especially if your garage is used for storage or other activities that could produce a lot of water. Floor drains come in different capacities, so be sure to choose one that is large enough to handle the amount of water you expect to generate.

Step by Step Guide: How to Install a Floor Drain in an Existing Garage

Step 1: Plan the Drain Location

Determine the optimal location for the floor drain in your garage. Ideally, it should be situated at the lowest point to ensure effective drainage. Use a level to find the area with the most slope. Additionally, consider the garage’s layout, traffic patterns, and proximity to plumbing for ease of installation.

Step 2: Check Local Building Codes

Before proceeding with the installation, consult your local building codes to ensure your planned floor drain complies with any regulations or requirements. Some areas may have specific guidelines regarding drain size, location, or materials.

Step 3: Gather Necessary Tools and Materials

Assemble the necessary tools and materials for the installation, including:

  • Concrete saw or jackhammer
  • Shovel
  • Floor drain assembly
  • PVC pipe and fittings (if connecting to an existing sewer line)
  • Gravel
  • Sand
  • Concrete mix
  • Trowel
  • Level
  • Safety equipment (gloves, goggles, ear protection, etc.)

Step 4: Cut the Concrete

Mark the outline of the drain opening on the garage floor using chalk or a marker. Ensure that the dimensions match the size of the floor drain assembly. Put on your safety equipment, and then use a concrete saw or jackhammer to carefully cut through the concrete along the marked lines. Remove the cut piece and set it aside.

Step 5: Excavate the Drainage Trench

Dig a trench from the drain opening to the point where it will connect to the existing plumbing system or discharge outside the garage. The trench should be wide enough to accommodate the PVC pipe and deep enough to maintain a consistent slope of 1/4 inch per foot for proper drainage. If connecting to an existing sewer line, consult local building codes for guidelines on appropriate connections and required slope.

Step 6: Install the Floor Drain Assembly

Place the floor drain assembly into the opening, ensuring it sits flush with the surrounding concrete. If the drain includes a sediment bucket or trap, insert it according to the manufacturer’s instructions.

Step 7: Connect to the Existing Plumbing

If connecting the floor drain to an existing sewer line, use PVC pipe and fittings to create the connection. Dry-fit the pipe and fittings first to ensure a proper fit, then use PVC primer and cement to secure the joints. Be sure to follow local building codes regarding proper connections and venting requirements.

Step 8: Create a Gravel and Sand Base

Fill the bottom of the trench with a layer of gravel, approximately 2-3 inches deep. This will help promote drainage and support the PVC pipe. Next, add a layer of sand on top of the gravel, providing additional support and preventing the pipe from settling over time.

Step 9: Install the PVC Pipe

Lay the PVC pipe into the trench, ensuring it maintains the appropriate slope for drainage. Use a level to confirm the slope and adjust as necessary. Secure the pipe to the floor drain assembly and the sewer line or exterior discharge point using appropriate fittings and PVC cement.

Step 10: Backfill the Trench

Cover the PVC pipe with more sand, filling the trench until it is approximately 2-3 inches below the garage floor surface. Tamp the sand down to provide a stable base for the concrete.

Step 11: Mix and Pour Concrete

Prepare a concrete mix according to the manufacturer’s instructions. Pour the concrete into the trench, filling it to the same level as the surrounding garage floor. Use a trowel to smooth and level the surface of the concrete, ensuring a seamless transition between the existing floor and the new concrete.

Step 12: Allow Concrete to Cure

Allow the concrete to cure according to the manufacturer’s recommended time frame, typically 24-48 hours. Avoid walking on or placing eavy objects on the new concrete during this time to prevent cracking or shifting.

Step 13: Seal the Concrete (Optional)

For added durability and protection, consider applying a concrete sealer to the entire garage floor once the new concrete has cured. This can help prevent moisture intrusion, staining, and surface damage. Choose a sealer compatible with your concrete type and follow the manufacturer’s instructions for application.

Step 14: Test the Floor Drain

Once the concrete has fully cured, test the floor drain by pouring water into it. Ensure that the water drains effectively and that there are no leaks or blockages in the system. Address any issues as necessary.

Step 15: Maintain the Floor Drain

Regularly clean and maintain your garage floor drain to ensure proper function and prevent clogs. Remove debris, such as leaves or dirt, from the drain cover and check the sediment bucket or trap (if applicable) periodically, cleaning it out as needed. If you notice slow drainage or standing water, investigate the cause and make any necessary repairs.

By following these steps, you can successfully install a floor drain in an existing garage, improving drainage and reducing the potential for water damage or pooling. Proper installation and regular maintenance will ensure the long-term effectiveness and functionality of your garage floor drain.

Additional Tips and Advice

Here we have given some tips on how to install a floor drain in an existing garage.

  1. Always use a floor drain when draining water from your garage.
  2. If you have an existing floor drain, make sure it is clean and clear of debris before using it.
  3. If you do not have a floor drain, you can install one yourself. Follow these steps:
  4. Find the lowest point on your garage floor and mark it with a chalk line.
  5. Drill a hole at the marked spot and insert the flange of the floor drain.
  6. Using a level, make sure the flange is properly aligned before tightening the screws.
  7. Connect the drainpipe to the floor drain and extend it out of the garage.
  8. Make sure the drainpipe is properly secured before using it.

Should You Hire a Professional to Install a Garage Floor Drain?

Installing a floor drain in your garage is not difficult, but it requires some knowledge and planning. If you are not familiar with plumbing or concrete work, it is best to hire a professional to do you. However, if you are comfortable with basic plumbing and construction skills, you can easily install a floor drain yourself.

The first step in installing a garage floor drain is to identify the location of the drain. The drain should be located in a low spot in the garage where water will collect. Once you have found the perfect location for the drain, you will need to mark the area around it, so you know where to cut the hole for the drain.

Use a hammer and chisel to create a big enough hole for the floor drain. The hole size will depend on the size of the floor drain you are using. Once the hole is cut, place the floor drain in the hole and secure it in place with concrete screws.

How Do You Install a Drain in an Existing Concrete Floor?

If you have a concrete floor in your garage that doesn’t have a drain, you may wonder how to install one. Drains are essential for garages because they allow water and other liquids to flow away from the area, preventing pooled water and potential flooding. Plus, having a drain in your garage will make it much easier to clean up any spills or messes.

If you’re ready to install a drain in your garage, here are the steps you need to take:

  1. Locate the spot where you want to install the drain. The best place for a floor drain is usually in the middle of the garage, near the door that leads into your house. This will allow any water or liquids to flow away from the door and into the drain.
  2. Mark the spot where the drain will go with a pencil or pen.
  3. Use a hammer and chisel to make a small hole in the concrete at the marked spot. The hole should be big enough to fit the drain’s catch basin.
  4. Place the catch basin into the hole and secure it with concrete screws.
  5. Attach the drain pipe to the catch basin and ensure it is properly secured.
  6. Cover the drainpipe with gravel or rocks to prevent any debris from clogging it up.
  7. Flush the drain with water to ensure that it is working properly.
Flush the Drain With Water

If you have any questions or concerns about how to install a floor drain in an existing garage, be sure to consult a professional before starting the installation process.

You Can Check It Out To Keep Water Out of Garage


Installation of a floor drain in an existing garage is not as difficult as one might think. It can be a relatively easy project that can be completed in just a few hours with the right tools and basic knowledge. First, measure the area where you want to install the drain and cut the hole using a jigsaw or circular saw. The hole should be slightly larger than the diameter of the drain to fit snugly into place.

Installing a floor drain in your garage is a great way to protect your investment and clean your space. If you’re thinking of installing one in your garage, be sure to follow the steps we’ve outlined on how to install a floor drain in an existing garage so that the job goes smoothly. Have any questions about the process? Leave them in the comments section below, and we’ll do our best to answer them.

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Rick Kelly

I am Rick. I grew up helping my dad with his handyman service. I learned a lot from him about how to fix things, and also about how to work hard and take care of business. These days, I'm still into fixing things- only now, I'm doing it for a living. I'm always looking for new ways to help people grow and develop. That's why I have created this blog to share all my experience and knowledge so that I can help people who are interested in DIY repair.

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