French drainage: what it is, how it works and how it is installed

French drains around the home are used to collect and divert groundwater, which can prevent various problems. Presented systems are often installed near the house to keep the basement or basement dry, but they can also be installed in wet lawn areas along the driveway. Building a french drain around the house is necessary to create a free-draining drain that can collect groundwater and redirect it to an established discharge point. 

If you want to create a french drain in front of your house, you’ll need our guide. In this article, we will break down all the system’s features, what gives its installation, when it is not suitable and how to do everything competently. 

How to install French drainage

French drain in the house is an underground pipe or trench where water is collected and sent to a special place for drainage. With this system, you can solve the problem of water accumulation, which can damage the foundation of the building. 

Installing a french drain around your house is required in the following situations:

  • water is constantly accumulating around the base of the building;
  • water does not run off from a hard surface to drain correctly (for example, rainwater will not run down the driveway);
  • water flowing down the slope creates considerable puddles in the yard, which harms your landscaping and creates certain inconveniences.

From the outside, the french drainage system for the yard looks like a drainage ditch in the rock. If approached correctly, it will fit perfectly into the site’s landscape design. A drainage pipe is installed in the gravel at a certain angle, so the water flows to the right place without harming the foundation or site. Install the submitted system on its territory so that the open end of the Treba drains water to the downward slope.

All components of the presented system are made so that water can quickly drain without accumulating in the trench. It is carried over stone or gravel through special holes in a perforated pipe. Wrapping landscape fabric around the pipe allows water to pass through and prevents plants and other things from clogging the holes. With the pipe, the water goes to a drainage area in the yard or goes straight to the sewer.

The advantages of installing a French system: why it is worth putting in

Underground french drain deals with the fact that it drains water from ground level, while gutters collect precipitation when it runs off the roof of the house. It is the best solution for a wet basement or foundation that experiences hydrostatic pressure, causing water to seep in constantly. The system presented allows water to be redirected away from the house. If the water still penetrates the basement, an interior french drain is installed – a trench is cut into the basement slab around the perimeter of the basement, a pipe is installed there, and a pump is installed to divert the water.

French drain yard installation has several advantages:

  • a collection of unwanted surface water, which prevents flooding of the patio, yard area, and driveway;
  • drainage of groundwater, drying the foundation and lawn;
  • the system can be added after the construction of the house;
  • almost no maintenance.

You need a french drain installed if your basement is constantly moist and damp, and fungus or mould has appeared, which are detrimental to the house’s condition and create particular difficulties for tenants.

In what situations is it not worth putting a French drainage

Only some sites can have a french drain between houses. It is not a one-size-fits-all solution to all drainage problems. The presented system, just like the gutters on the roof of the house, is designed for the main task – the diversion of water in a particular place where it will not harm the condition of the structure or site. Therefore, a particular slope for unimpeded drainage of water should be on the site. If not, the ditch will collect water in itself, which will only worsen the problem.

During the planning of the installation, it is undoubtedly worth determining where precisely the water will be drained. It can be:

  • street;
  • city sewer;
  • a particular area on the site (next to the tree, into the garden, etc.).

In no case should the water not flow into the neighbour’s yard. If you do not have a suitable place for the discharge of water, then it is not suitable for your area.

What materials will be needed for installation

The long french drain requires the use of special perforated pipes. The perforation comes in 2 types: slotted or circular. The first option is preferred because it does not allow a large amount of soil to get into the pipe. To install this system, it is worth using the following materials and tools:

  1. drainage pipe (most often take the product 6 feet in length, but you can also take more if necessary);
  2. landscape fabric – a roll;
  3. bright spray paint;
  4. shovel;
  5. landscape stones;
  6. sand;
  7. gravel;
  8. topsoil;
  9. lawn.

You can buy suitable French drainage pipes with or without a filter in construction stores for further installation. 

The process of installing French drainage: the main steps

Installing french drain around the house – quite a feasible process, which you can learn. This work can be done independently, using suitable tools and unique materials. Before installing a french drain in the yard, you should first understand whether you need permission from the municipality for this project. Most often, communities allow these outdoor drainage systems, but there are also specific areas near wetlands and other sensitive areas where it cannot be done.

No. 1: Find a suitable area on the property to redirect excess water

Installing a french drain in the backyard begins with finding a suitable area to divert the water. It is required to determine a route with a slight slope, at least 1 meter from the house’s walls or fences, with no obstacles. Use spray paint to determine the drainage route.

No. 2: Dig a trench and fill it with gravel

Whether you’re installing french drains for gutters or other systems, they all work on the same principle. When you’ve outlined the trench with paint, take a shovel in your hands and start creating a trench with a slope in the direction where the water should be diverted. The optimum is 1 inch for every 8 feet of route. To determine a clear slope, you can use a level string tied between stakes, measuring the distance from the reference point. The depth should be 18 to 24 inches.

No. 3: Lay a lining of fabric

Put landscape fabric on top of the gravel throughout the trench, leaving 10 inches of fabric on each side. This material will help prevent weeds from growing.

No. 4: Install a drainage pipe

Creating a linear french drain is definitely worth installing a pipe. In this situation, you can use complex PVC products with drilled holes or a special flexible drainage pipe with slots. PVC products will last longer because they can be cleaned with a sanitary snake in the case of clogging. But the advantage of a flexible pipe is that it is cheaper and a little easier to work with.

After installing the pipe, some gravel should be poured on top of it. The material should cover the pipe.

No. 5: Properly stack leftover fabric

Fold the excess fabric over the gravel, creating an overlap at the ends. This way, it will be possible to protect the drainage pipe from the penetration of soil and plant roots.

No. 6: Backfill the trench

Finally, the trench should be backfilled with gravel, smoothing it out. Another option is to backfill the gravel within a few inches of the ground level. Then you can backfill the soil to level the surface. 

Expert tips on how to properly install a french drain

If your home requires a french drain system and you want to install it yourself, it doesn’t hurt to read some professional advice before the process:

  • the trench should be the right size – the best option is at least 2 feet wide and up to 6 feet deep (if you are digging it for a basement) or no deeper than 2 feet (if you are creating a slab home drainage at ground level);
  • create the proper slope – the pipe should be sloped from a higher starting point to a lower one at the end so that the water flows under gravity. The slope should always be made away from the house;
  • The pipe should be backfilled with gravel, a layer that should be at least 12 inches.


A french drain to divert water is self-explanatory and relatively easy to install if you get it right. Following the above steps, you can implement the presented project
with your own hands. But in this situation, it also does not hurt to take some helpers to help you with the installation.