Digging a trench for drainage is an effective way to prevent water from flooding your yard, as a flooded yard can erode your home’s foundation and cause many health issues.

This is why it’s important to know how to dig a trench for drainage so that water drains away from your compound without damaging your neighbor’s property. Depending on the tools and equipment you have on hand, you can either dig a drainage trench by hand or by using a machine.

This guide will go over digging a trench in your yard to drain away any excess water.

How to dig a trench for drainage pipes

Digging a drainage trench can be a straightforward task, but it’s important to first confirm what permits are required. Different cities and states have varying permits, so it’s crucial to check this first. Once you’ve done so, you can follow these steps to start digging for drainage pipes.

Step 1: Plan the drainage trench

Think about where the excess water collects in your yard and plan where to dig the drainage trench accordingly, ensuring that the directed water won’t damage your neighbor’s property.

Plan to channel the water flow downhill, away from the flooded point. You can use a level to find the proper drainage slope for the trench before digging. This will help you plan your drainage trench more efficiently. 

Ensure the canal will be free of obstructions.

Step 2: Determine the trench depth and slope

The next step in how to dig a trench for drainage pipes is considering how deep you want to dig your drainage trench. 

Drainage trenches are usually about 18 to 24 inches deep and 12 inches wide. The depth of the trench should be at least 18 inches to allow room for:

  • A gravel base
  • Drain pipe
  • Rock gravel
  • Topsoil

It helps to think about the slope of the trench, which should be at least 1 inch per 10 feet run. This ensures the outlet will be at least 10 inches deeper at the end of a 100-feet run. More slope means a deeper outlet, requiring more gravel.

Step 3: Assemble your trench-digging equipment

When it comes to how to dig a trench for water drainage, you’ll need the right tools. These tools include:

  • A hoe: Smoothes out the drainage trench and rock gravel
  • A level: Keeps the slope consistent from the inlet to the outlet
  • A spade: For removing soil from the trench and refilling it with gravel
  • A tape measure: For measuring the length, width, and depth of the trench
  • A wheelbarrow: For hauling out excess dirt and hauling gravel into the trench
  • Work gloves: To protect your hands from blisters when digging the trenches

If you plan to dig the trench by hand, you’ll need a trench shovel to cut through the soil and a grub hoe to break hard-packed ground soil. A flat-bottom shovel will also help you clean the trench and keep the bottom layer smooth and flat.

Step 4: Dig the drainage trench

Now that you have a plan for how to dig a trench for water drainage, it’s time for the actual digging. Use the tools designed for digging trenches, ensuring your trench is deep and wide enough to accommodate the drainage pipe. 

Here are the trench dimensions to consider:

  • Depth: 18 to 24 inches
  • Width: 9 to 12 inches
  • Slope: 1 inch per 10-feet run

Check your slope regularly when digging to ensure it’s uniform. If excavating the trench on flat ground, deepen it in the direction you want the drained water to flow. Also, if the land is too dry, consider watering the digging points first before starting to dig.

Step 5: Line the trench with landscaping fabric

Once you’ve dug the trench, the next step in how to dig a trench for drainage is lining it with water-permeable landscaping cloth. The fabric will protect your plumbing from tree roots. Otherwise, invasive grasses and plant roots can clog and damage the drainage pipes.

Since you don’t want your hard work to go in vain, you can have excess landscaping fabric, which you’ll use to cover the gravel in the next few steps.

Step 6: Add gravel at the base of the trench

Add 3 to 4 inches of gravel at the trench’s bottom, on top of the fabric liner, to provide a base for the pipe. This is especially useful for French drains that allow water to filter through the perforations before filtering into the soil beneath.

Step 7: Install a drainage pipe

When considering how to dig a trench for drainage, the purpose of the drain is to receive water that’s flooding your yard, redirecting it elsewhere through the drainage trench. 

So place the pipe’s inlet near a gutter downspout or in a wet or flood-prone area in your yard to draw in water.

Install a drain grate at the inlet to prevent debris from passing through. Also, ensure that the pipe rests on the gravel base and connects to the water outlet. If it’s a perforated pipe, ensure its holes face downwards.

Step 8: Cover the pipe and trench with gravel 

Now that the pipe is secure, it’s time to cover it with an additional 3 inches of gravel. This will protect the pipe and allow for proper drainage when perforated. Next, you can use the excess landscaping fabric in step 5 to cover the gravel and pipe.

At this point, you’re free to cover the whole trench with any material you wish. It could be more gravel, stones, or soil. You can even plant some grass on top of the soil covering the trench.  

Consult expert plumbers at J. Blanton Plumbing

Now you know how to dig a trench for drainage pipes. Since digging a trench can be labor-intensive, consider hiring a professional to do the job. 

Let J. Blanton Plumbing help you! Our expert plumbers are up to the task. Contact us today to schedule your trench-digging project for drainage pipes.