These rocks will keep your French drain flowing freely
Are you preparing to install a drainage system and wondering which type of rock is best for French drains? The type of rock used in your French drain is essential because if you choose the wrong type, it can cause issues and prevent your drain from working effectively.
So, don’t stumble over all the rock choices. Learn which are the best rocks for French drains and which are the worst ones so you can avoid potential issues and an unnecessary purchase.
It may surprise you to learn that only two types of rocks are recommended for use in French drains, simplifying the decision-making process. Let’s dive into the two most popular rocks to use for this drainage system:
River rock tops the list of the best rocks for installing in French drains. Natural round rocks are ideal because their size and shape allows the water to drain more effectively. It’s vital to use washed rock because it has been cleaned of debris and particles, which will help prevent clogging the drainage system. River rock is also durable and can thwart off the erosion effects of water. The average cost for a ton of river rock ranges between $100 and $800, but may vary depending on your location.
| Pros | Cons |
|---|---|
| Allows water to drain effectively | Costly to install, but less than granite chips |
| Durable and withstands water erosion | Availability may be limited based on your region |
| Already cleaned and prevents clogs | Allows debris to accumulate if not properly installed |
Best for: Homeowners installing a French drain on a budget
Granite chips are another top pick when it comes to the best rocks for French drains. Granite is also a hard rock that is durable and resistant to erosion. Due to the shape, size, and density of granite chips, the material allows water to flow freely, which ensures the drain works efficiently and prevents clogs.
However, granite can be more expensive than river rock, so you will want to compare prices and determine which type of rock is best for your project and budget.
| Pros | Cons |
|---|---|
| Shape of the rock allows adequate drainage | More expensive than river rock |
| Resistant to erosion | Clogs if you use the wrong size |
| Aesthetically pleasing | Availability may be limited based on location |
Best for: Homeowners prioritizing aesthetic appeal of French drain
Rocks that are too small and dirty can cause issues and prevent proper drainage. So, now that you know the best rocks for French drains, let’s explore which ones you should skip.
For water to flow freely, there needs to be adequate spacing between the rocks. Pea gravel is not a good choice to use for a French drain because the size of the rocks are too small. It also compacts more easily, which prevents proper use of the drainage system.
While pea gravel is eye-appealing and excellent for other landscaping projects around your home, such as walkways, you should skip using it for your French drain system.
While limestone is a durable rock, it is more susceptible to erosion than other rock types. Acidic rainwater can cause limestone to dissolve and erode faster. As it breaks down, the fine particles can wash into the drainage pipe, causing clogs and preventing it from draining properly.
Limestone can be a great choice for other landscaping purposes, such as decorative rock gardens or pathways, but you want to avoid using it in your French drain installation.
The size of the rocks is as vital as the type of rocks for your French drain. The best size rock to use for French drains is between ¾ inch and 1½ inches. If the rocks are too small, they will not allow proper water flow, which prevents efficient drainage. Rocks should be large enough to create space between them to allow water to flow freely and prevent blockages. Consult a local French drain installer to ensure the rock type and size is a good fit for your drainage needs.
If you are dealing with shallow water issues, a French drain may be used with rocks and no pipe. However, for areas that experience large amounts of water or heavy rainfall, you should use a corrugated or PVC pipe in the French drain. The pipe helps redirect and distribute the water effectively to another area, which can help prevent pooling water in your lawn and around your home.
Using filter fabric is highly recommended because it helps prevent debris and sediment from clogging the drain. It’s best to use a non-woven geotextile landscape fabric for your French drain because it is designed to allow water to flow through but not soil particles and other debris. It’s durable and long-lasting, which is why it’s the top choice for French drains.
While it’s possible to install a French drain yourself, you should opt for hiring a professional if you need a large complex drain system installed. French drain installers have the necessary expertise and tools required to install the drain correctly, so you won’t have to deal with the consequences if you install it incorrectly.
