How To Install Garage Trench Drain

trench drain for the garage

It’s disheartening to discover that your garage floor is causing water to accumulate on the floor.

This could be as a result of your garage being situated at the bottom of an incline, so when you wash your cars or use water for other purposes this can cause water to linger around. To help to remove it, you could install a trench drain. 

What is a trench drain?

A trench drain is a type of drain that is installed in the ground or floor to remove water and other liquids quickly. It makes use of a channel-shaped body to achieve this

You might want to install a trench drain in your garage to eliminate water or even chemicals so they don’t lead to problems. Here’s everything you need to know about how to install a garage trench drain yourself.

Why You Need To Eliminate Excess Water From Your Garage

water drainage in garage floor

If lots of water is building up in or outside your garage on a regular basis, this insufficient drainage can cause you big problems in future, such as damage to the building foundations.

Water could end up accumulating underneath the foundation of the home or property, which could result in the soil swelling.

When this happens, the foundation could actually crack and lead to excessive flooding. Water that enters your garage uninvited can also damage your possessions that you store there, such as your car – its interiors could be ruined by it.

It therefore makes sense to install a trench drain because it will save you money on those types of expensive repairs on your home that you really didn’t budget for! 

Luckily, you don’t have to reel in the professionals – you can install your own trench drain in your garage by yourself. 

How To Install A Garage Trench Drain – Step-By-Step Guide 

If you want to build your own trench drain, you’ll have to ensure you have all the right tools and items on hand. Here’s what you need: 

  • Tape measure 
  • Chalk 
  • Concrete saw
  • Jackhammer
  • Shovel 
  • Sand
  • Concrete screeding tool 
  • Drain (with grate) 


  1. You’ll have to start by measuring the floor of your garage where you want to put your trench. Use chalk to mark lines for the outside edges of the trench. 
  2. How big should your trench drain be? A good guideline is to consider that the average drain trench will be about six inches wide.
  3. Now, if you’re hoping to eliminate a large amount of surface water that always accumulates in the area, such as in front of your garage doors, then it’s a good idea to build the trench at an angle that’s greater than 90 degrees (via Hunker). This will ensure that the water run-off will be distributed equally along its length. 
  4. Take your chalk again and draw two more lines that are four inches on the outside of the first ones you drew (via SFGate). These are important because you’re going to have to cut the trench wider than the drain width in order to lay down concrete to keep it securely in place in the ground.
  5. You’ll now use a concrete saw to cut both of your outside lines that you’ve drawn. 

Tips for using a concrete saw: 

trench drain in garage floor
  • Make sure you use the right blade. A diamond blade will make your job much easier. 
  • Start with one surface cut so that you’ll be able to break through the hard, compact nature of the concrete. 
  • When you continue cutting the concrete, make sure you retract the blade and let it run freely every 30 seconds so that it does not overheat.
  1. Once you have used the concrete saw, you can use your jackhammer to break the concrete of the garage floor in the space between the two lines that you’ve cut. 
  2. Make sure you remove concrete debris from the trench. 
  3. Get enough sand to fill the bottom of the trench and make sure you level it. You should have a layer that’s approximately two inches (via SFGate).
  4. Now you need to assemble your drain sections inside the trench. Some will have rods that you push into the ground with the use of a tool like a mallet, while others will just rest on the bed of sand you’ve laid down. 
  5. You’ll be able to purchase corners and bends of drains so that you can fit them according to the design of your garage, such as so that they can move around the walls
  6. Remember that your drain needs to have an exit on at least one side of the garage so that water will be able to run out! 
  7. Most trench drains you’ll purchase will have an iron grate in place that must not be higher than the garage floor level, so make sure you put it in place and keep it level.
  8. Now you can go ahead and fill the sides of the trench with wet concrete. Work it into the ground with a shovel. You need to push it down and tamp it so that it doesn’t form air bubbles.
  9. Make sure you screed the wet concrete on top to ensure it is even and in line with your garage floor as well as the top of your drain. To screed concrete, you’ll have to make use of a long and straight board or aluminum bar so that you can draw it across the wet concrete.

Bear in mind that you’ll need to allow the concrete you’ve applied to set for 14 days, so make sure you’re installing this trench drain in an area of the garage where you won’t have to drive your car over it.

You might have to store possessions you’ll need from your garage elsewhere in the home during this time. 

Where To Find Trench Drains

finished trench drain

While you’ll be digging and setting up your trench drain yourself, you’ll need the actual drain. Luckily, you can find lots of different types on the market, such as on Amazon. 

An example is the US Trench Drain kit that is designed with flat grates and smaller slats that aren’t a high-heel risk because they’re small enough so that heels won’t get caught in them.

This drain kit makes installation easy because it’s got a design that clips together and it doesn’t need staking when you’re setting it into concrete. People who have reviewed this product on Amazon have stated that they used it to remove water from their garage and it worked very well.

Another good drain to purchase is the NDS Pro Series Drain Kit. It has been designed to carry a moderate amount of water away from hard surfaces.

You can cut it into smaller sizes, as small as four inches in length, if you need to make use of smaller sections. It’s easy to install because it makes use of interlocking joints and you don’t require any couplings. 

Related Questions 

What’s the difference between a trench drain and a French drain? 

installed french drain

A trench drain is built to quickly eliminate surface water before it can accumulate or saturate the ground, while a French drain collects and removes the groundwater. Trench drains are on the surface of the ground while French drains are below the surface. 

How can you keep your garage dry during the rainy season? 

There are some important things you should do to prevent water from getting into your garage in other ways.

These include making sure you seal up any cracks, insulating the doors and windows, checking that the doors seal properly when closed, and setting up a dehumidifier to keep moisture away.

Is it more expensive to rent a corundum blade for your concrete saw? 

If you need to rent a blade for the project, you might consider a corundum blade. While corundum blades are cheap, they turn out to be more expensive as compared to diamond blades on a per-cut basis, as The Family Man reports.


If you’re sick and tired of water entering your garage and staying there, you need to build your own trench drain.

Luckily, this isn’t a difficult or time-consuming project. In this article, we’ve provided you with a step-by-step guide on how to build your own garage trench drain as well as some products you should consider purchasing to make your job even easier. 

Stop letting water accumulate in your garage where it can cause a nuisance and damage your foundations. Now that you have all the info you need to set up your own trench drain, you’ll be able to store your possessions in your garage without a worry and make your garage much more useful.

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