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Retaining Wall Drainage: How To Drain Water Properly

Note: This post may contain affiliate links. This means that at no cost to you, we may receive a small commission for made purchases.

Retaining walls are often built to prevent erosion or soil movement from occurring along a slope. They are also commonly used to create terraces or steps.

Retaining walls are constructed using various materials such as concrete, stone, brick, wood, steel, and other natural and manmade materials.

Retaining walls come in many shapes and sizes. Some are designed to support landscaping, while others are meant to provide structural stability.

The type of retaining wall you choose depends on several factors, including the size of the area where you want to build it, the amount of load it will bear, and the climate conditions in your region.

If you need to know how to drain water properly from your retaining walls, you’ve come to the right place. Stick with us to learn how to keep your retaining walls clear and drain water correctly. 

What Is Drainage?

Drainage is the process by which water flows away from a structure. This can be done through gravity, pumps, or pipes.

Gravity drainage is when water naturally runs downhill towards low points in the landscape. Pumps use mechanical force to move water uphill against the direction of gravity.

Pipe drainage uses pipes to direct water into a lower point in the landscape.

Why Do Retaining Walls Need Drainage?

A retaining wall is essentially an artificial hill that prevents soil from moving downslope. If there isn’t any drainage system in place, this could cause problems for your retaining wall.

For example, if too much rain falls during heavy storms, the soil behind your retaining wall may become saturated. 

As this happens, the weight of the soil above the wall increases, causing the soil to shift. When the soil shifts, it can damage your retaining wall.

How Does Retaining Wall Drainage Work?

There are two main ways to drain water out of a retaining wall. One way is to allow the water to flow naturally around the base of the wall. This is called free drainage.

It’s important to note that free drainage doesn’t always work well. In some cases, the ground beneath the wall may not have enough space to accommodate all the water.

Another way to ensure sufficient drainage in a retaining wall is to allow water to pass straight through it.

This can be done by using loose pack materials to build the wall, or by installing a pipe that facilitates water flow from one side to the other.

How To Drain Water From A Retaining Wall 

How To Drain Water From A Retaining Wall

The first method of draining water from a retaining wall involves installing drains at the base of the wall to collect excess water.

These drains are usually placed near the top of the wall to ensure they’re located below the level of the surrounding land.

Once the water collects in these drains, it can then be pumped up to higher areas.

In order to install drains at the base of a retaining wall, you’ll need to dig trenches in the soil. You should make sure to leave about 6 inches between each trench.

Next, you’ll need to cut holes in the side of the trench. Make sure to drill straight down into the center of the hole. Then, you’ll need to insert a pipe into the hole.

Finally, you’ll need to fill the hole back in.

Another option for draining water from a retaining wall is to install perforated pipe along the length of the wall. Perforated pipe has small holes drilled throughout its length.

The purpose of this pipe is to help water pass through the wall while still allowing air to circulate.

You’ll want to install a perforated drainpipe at least every 20 feet along the length of the retaining wall. This will help prevent water from pooling in one spot and building up pressure.

What Are Some Common Problems With Retaining Wall Drainage?

If you don’t properly design a drainage system for your retaining wall, you might experience some common problems.

First, you might find that water pools in certain spots on the wall. This can occur because the drains aren’t positioned correctly.

Second, you might notice that water builds up in the area just below the wall. This occurs because the drains aren’t deep enough.

Third, you might notice that the soil becomes wet when it rains. This is caused by the fact that the drains are located too close to the surface.

Finally, you may find that the soil underneath the wall begins to dry out after a long period of time. This is caused by poor drainage or improper placement of the drains.

How Do I Know If My Retaining Wall Needs Drains Installed?

Before you start digging trenches and drilling holes, it’s best to take a look at your existing drainage systems. If there aren’t any, then you’ll probably need to install new ones.

When it comes to finding out if you need drains installed, you can use a few different methods.

First, you can check with an engineer who specializes in designing retaining walls.

They can tell you whether or not you need drains installed based on the type of soil you’ve got and how much weight your wall holds.

Next, you can contact a local landscaper who specializes in installing retaining walls. He or she can give you advice on what kind of drains would work best for your situation.

Finally, you can ask your contractor to do a free inspection. He or she will be able to tell you whether or not your current drainage system is working well.

If you have limited experience with retaining walls, we always recommend contacting a contractor for a free inspection before hiring an engineer or attempting any repairs yourself.

This will ensure you’re treating your walls appropriately and not causing any lasting damage to your walls or your property. 

Final Thoughts 

There are many ways to drain water away from a retaining wall, including installing perforated pipes or installing drains right at the base of your wall.

However, we would always recommend seeking professional assistance before making any permanent changes to your walls.

We hope this guide has provided a useful way for you to drain your retaining walls and keep them functioning smoothly in the future! 

author avatar
Anthony Barnes
Anthony Barnes is the founder of Water Heater Hub and a second-generation plumber by profession. Before developing Water Heater Hub, Anthony Barnes was a full-time plumber, and he has undertaken a wide variety of projects over the decades. As a second-generation plumber, it was easy for Anthony to get used to the technicalities of all from a tender age


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