Gravel for a French drain (AVOID Doing This!)

What is a French drain?

A French drain is known as an agricultural drain, blind drain, drain tile, filter drain, French ditch, French drain, land drain, perimeter drain, or rock drain in different parts of the world. The other names for French drain are- rubble drain, weeping tile, sub-surface drain, or sub-soil drain. A French drain is a trench filled with gravel or small pieces of rock, or sometimes both. The pipe contains perforations that face down so that rainwater can enter them and keep your backyard clean.

Watch this video to understand the concept better-

French drains are extremely vital for building structures as they stop ground and surface water from entering or spoiling building foundations. They also function as an alternative to open pits or storm drains for roads and highways. They are also used to distribute water or are used behind absorbent walls to discharge groundwater pressure.

Why is a French drain required in a yard?

A french drain keeps your garden and walls dry. After a heavy rain or heavy snowfall when the snow starts melting with the rising sun, your yard will be filled with puddles of water. This will create large areas of mud and standing water. If the water is unable to drain away from the yard, it may flow towards the home, and if your home is situated at a lower level, it might even enter it. Stagnant water might even spoil the foundation of the home and if it stays for a prolonged time period the same stagnant water can lead to damaged walls.

A French drain can give you peace of mind as it can take the water away from the main structure of the building. Even your children and pets can play in the yard without any worries if there are no puddles. Otherwise, children love to play in puddles and they might bring home a lot of germs and fall sick. The French drain also reduces standing water in the yard, by sucking in water from the saturated ground in the adjoining areas.

You should use the French drainage system if you have the following situations-

1.    Recurring flooding causing damage even to the foundation.

2.    When there are puddles created by excess rainwater or melted snow, French drains pulls in water from the saturated soil. This saturated soil was unable to allow the water to seep into the ground levels, and hence the puddles were formed.

3.    Retaining walls hold soil in place and prevent erosion, however, if the soil is overly saturated due to stagnant water, this starts exerting pressure on the retaining walls, and they start becoming weak. French drains help to suck in all the water and increase the life of retaining walls.

Some of the best gravels for your French drain: pebbles and rocks

Now since you understand the importance of French drains, you would like to know the types of gravel you would need to install a French drain in your garden or yard. We have compiled some of the best gravels which are long-lasting and cost-effective.

French drains work by the mechanisms of gravity and work well if there is about a one or two-degree downslope. If you use layers of filler rock and sand (bottom layer), it will help the pipe to prevent blockages. It will be a good idea to put a layer of sod and larger pieces of rock (top layer) around the entrance and exit area of the drainage system. It will keep the pipe protected and maintenance-free for a longer duration. It can also make the French drain look nicer. Crushed rocks are often used for the bottom layer and they don’t look that nice.

Hard rocks such as granite or river gravel are known to be best to install French drains. They don’t break down as water passes through or above them and are sturdier than many other types of rocks like sandstone or limestone. River rocks already have withstood the test of time, and don’t erode easily. The best gravel size for french drains is small rocks and pebbles of 0.5 inches to 1 inch.

Make sure to use enough stones for your Fench drain. Crushed stones work best for the bottom layers as they won’t move around. You can use more beautiful rocks on top of this. Make sure to get the right type of nonwoven textile. This should let water flow in your garden while keeping the dirt out of it.

1.    Pea Gravel: lower level

Pea gravels are good for French drainage systems as the size is perfect for the project. It is even cost-effective if you have a large yard, you will need to have a large coverage area with the French drainage system. Using expensive gravel will increase the total cost of the project which will not even fetch a return on investment when you try to sell your house.

2.    Pink Quartz: upper level

Some homeowners prefer pink quartz because it looks great. It comes in several shades of pink, however, is not smooth and hence is perfect for the upper layer. It stays in place even if there is a heavy flow of water. The only flip side of this type of gravel is its cost. However, for the beautiful look, a little cost is often considered justifiable.

3.    Northern Granite River Rock: upper level

As the name suggests, this type of rock comes from the beds of rivers and other water bodies. Since these stones are hundreds of years old and rolled along with the flow of the river, their edges are not sharp. They were rounded by the flowing water. Since they have a smooth structure, they get displaced a lot. They look good, however, you will need to refill the stones after a few seasons of rainfall or snow.

4.    White Dolomite: upper level

This type of stone unlike many other colorful stones does not add to the oomph aspect of the project. The stones are white in color and are perfect for any French drain project.

They can discolor after a few years, making them look less appealing if they don’t get cleaned with a pressure washer.

5.    Crushed Stone #411: lower or upper level

Crushed stone #411 is a quite popular variety for multiple landscaping projects because it has small pebbles plus dust. The dust and smaller stones fill up the gaps created by the larger stones and the pavement does not move much. It is quite affordable and most homeowners use it as a bottom or top layer for the French drains. It does not have any aesthetic appeal as it looks like normal gray-colored stones.

Photo by Mitch Fox on Unsplash


You may choose to hire a contractor to lay French drains in your yard or you may do it yourself. Whatever you choose to do, you need to keep in mind that the French drainage system should be installed before the rainy season arrives. If you live in an area that receives snowfall, you should always install a French drain in your yards to safeguard your flower beds and the foundation of your precious home. Installing one should take a few days.

You have to use enough stones and also add fabric so that your French drain will last a long time. Most people don’t use enough stones and this makes the water flow slower. This can damage your garden or walls.

French drains are becoming more popular as they are quite easy to install and work really well. They are able to keep your garden dry and avoid sinkholes. It is essential that you install them correctly though. A big part of this is picking the right gravel and rocks so that it is stable and can transport water away from your garden. A french drain is often connected to the city sewer system so that the water can be flushed away.


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