What is a French drain system? Find out the answer to these plumbing questions below.

What Is A French Drain System, Industry Today

A good drainage system is important for a variety of reasons. Not only does it help divert water away from a building or structure, but it also helps prevent foundation problems. For example, if you have a weak foundation, and water gets collected in the basement over time, there’s a huge chance that your building will suffer structural damages over time.

When water collects at the bottom of a basement, it may become stagnant and may eventually fill the space with moisture. This could result in infrastructure problems and even health issues. So, to avoid that from happening, you need a good and reliable drainage system. One of the best ways to create a good drainage system is by installing a French drain. But what is a French drain system and how is it different from others? Find out the answer to these plumbing questions below.

What Is A French Drain System?

A French drain system is a subsurface solution that consists of a perforated or slotted pipe and a gravel-filled trench. A permeable fabric serves as a protective layer, and this is installed at the sides and the bottom of the trench drain after excavation to prevent root and soil intrusion. Similar to trench drains, French drains draw water downhill, including surface and groundwater.

French Drain vs Trench Drain: What’s the Difference?

Drainage systems commonly include Trench drains and French drains, which are both very effective approaches in moving water offsite. However, the difference between the two is usually misunderstood.

Listed below are the following differences between Trench drains and French drains:

  • Structure Location: Trench drains are different from French drains in such a way that the former are surface structures whereas French drain systems are found in the subsurface. French drains can range in depth, they could be about a foot wide.
  • Water Drainage: Trench drains are called channel drains which are above-ground drainage with their actual plumbing materials embedded into the ground. It involves excavating a long, narrow trench with a grated cover finish. Trench drains give the impression of having a large ground guttering, redirecting water away from where it could potentially cause safety risks. Aside from that, French drains are also tough like trench drains and it has the ability to handle the hydrostatic pressure of groundwater or the pressure exerted by water due to gravity.
  • Uses: Both Trench and French drains are effective pipes used to redirect water away from the site. They help prevent damage to the foundation. Once the trench drain is dug and laid, you should connect it to a local storm sewer or waterway. In this way, the water is redirected away from the site without causing damage to the ecosystem. Since French drains are embedded more deeply into the ground, they help siphon accumulated water from the surrounding earth to prevent soil erosion and ensure structural stability.

How To Install A French Drain

Installing a traditional French drain involves excavating a trench for more effective and convenient drainage of areas such as flood plains and surface water. Naturally, this would require professional expertise. French drains are generally quite small or extremely large, depending on the volume of water that has to be drained and the volume of ground space that has to be cleared.

If you are curious to know about how a French drain is installed, here’s how to do it:

  • A typical installation starts with a straight cut through the soil. The width of the drain depends on the volume of ground space that is required for proper drainage.
  • A drainage pipe will then be installed through the trench. The drainage pipe carries away rainwater which has been collected in the area around the drain. The length of the drainage pipe can vary, which is generally measured from the bottom of the drainage pipe.
  • After a drainage pipe has been installed, it is covered with a concrete drain liner. This layer acts as a temporary barrier against the excess water that may be discharged.
  • Once the liner has been added, it is attached to the drain pipe. This sealant acts as an absorbent layer against any water that may leak into the drainage system. This prevents any water from getting inside the drainage pipes.
  • Once the concrete drain liner has been applied and properly secured in place, a drain trap can be installed along the drain pipe. The trap contains special holes or slots for the drainage pipes to be fitted. These holes are usually positioned at regular intervals on either side of the drainage pipe.
  • Once the drainage trap is in place, the drainage pipe can be fitted and secured in place. The end of the drain pipe is then connected to a drain field.


French drains are below-the-ground pipes that redirect water away from an area or establishment, like your home or office building. It is used to ensure that any water that builds up under the ground will be eliminated. This avoids negative impacts on the foundation and other surrounding structures in the area.

Glenn Price, Industry Today
Glenn Price

Glenn Price is a blogger who regularly writes about business in different online platforms. Aside from updating his own blog, Glenn also submits content to countless business-focused websites.

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