Drain Rock: What It Is and the Best Uses

A rock is a rock is a rock…right?


While there might not be that much of a superficial difference between your “everyday rocks” laying all over your property, there’s a world of difference between how different kinds of rocks are used – especially when it comes to drain rocks.

To the surprise of no one, the whole point of drain rocks is to drain water from your property. These rocks allow water to move through a very specific stretch of land, away from your foundation and either into a traditional drain and culvert, a holding area, or just to a different piece of your property that you don’t mind getting a little wet.

And while tons of different kinds of rocks can be used in a drainage set up, some rocks do a better job than others.

Over the hundreds if not thousands of years that people have been using rocks for drainage we’ve figured out a thing or two about which ones work best for the specific application.

If you’re curious about drain rock, what it is, how it works, and how people use it you’re going to love the inside information we highlight below.

What is Drain Rock?

As we highlighted a moment ago, drain rock is a very specific kind of rock specifically used in drainage systems all over the country (and all over the world, really).

This collection of rock usually mixes bigger rocks with smaller and even absolutely tiny rocks, creating a unique texture that works well to move water efficiently. On top of that, these rocks are extremely porous by nature. That allows drain water to move with complete freedom in a way that would have been tough to do otherwise.

The overwhelming majority of drain rock available today is commercially packaged and processed.

Most of the time it’s “built” by crunching up bigger chunks of gravel into multiple smaller pieces, sifting those pieces and sorting them by size, and then combining them in a commercial drain rock mix with specific ratios.

Every manufacturer of this drain rock material has their own specific ratio that they like best, but most of them go heavy on the bigger rocks, have a decent amount of medium-size rocks, and then fill things out with pebbles and gravel dust.

Best Use Applications for Drain Rock

Now that we have covered all the basics when it comes to what drain rock is it’s time to go over how drain rock is used these days.


If you really wanted to it would be possible to build an entire driveway with drain rock – though you’d end up spending a lot more money than you might have otherwise. This is really the kind of job better suited to smaller bits of gravel as opposed to drain rock specifically.

At the same time, you will want to make sure that drain gets used along the periphery in the edges of your driveway. This is doubly true if your driveway is made of a solid manufactured material like cement or pavement (or even if your driver is made of clay).

An impermeable and solid manufactured material is going to shed water like crazy. These kinds of driveways are often pitched to one side or another (sometimes both sides get pitched with a slight hump running down the middle), and you’ll want drain rock on the perimeter to catch that water and run it off in a very specific direction.

It also adds a high quality look that’s tough to beat!

French Drains

Even though you may never have seen a French drain in action before the odds are good (very good) that you’ve walked on top of one without even realizing it!

French drain systems are relatively simple drain platforms used to keep water away from the foundation of a property. An ancient form of drainage that does just as good a job today as it did hundreds of years ago, French drains involve a couple of core components:

  • A trench deep enough for perforated pipes to be run through
  • Drain rock above and below that perforated pipe
  • A bit of topsoil, grass, and side to cover the drain rock up top to make the system “invisible”

The end result is a highly effective system for moving water away from your foundation (preventing it from causing damage) without having to have aboveground pipes, deep trenches, or other drainage systems all over the place.

Drain rock guarantees that the perforated pipes are able to shed water effectively without getting gummed up. They also do a good job of preventing settling and erosion.

Leach Fields

The right mixture of drain rock makes leach fields possible.

A core component of every effective septic system, leach fields are necessary to allow wastewater to become diffused out into the rest of your soil over time.

By using drain rock (anywhere between three quarters of an inch up to 2 ½ inches in diameter) in a field you’re able to create enough space for this leaching to happen to begin with.

Septic professionals will make sure use the right rock (and the right amount) for your leach field, allowing the gravel and the drain rock to do the heavy lifting of dispersing your waste water and solids so that you don’t have anything to worry about.

Gardening Spaces

There are a lot of newbie gardeners that get skeptical about using drain rock in their gardening space.

After all, isn’t the whole idea here to make sure that your plants have plenty of water to not just survive but thrive? Wouldn’t draining that water away choke your plants out?

Not really.

In fact, when installed correctly, drain rock has the ability to help your plants lead happier and healthier lives with bigger and bigger yields.

You see, too much water in the soil for some plans is as much (if not more than) of a problem than having too little.

Strategic pockets of drain rock can guarantee that heavy rains aren’t going to drown your delicate plants. The pockets of drain rock in a garden can also be used to prevent soil erosion, to help add structure to a garden space, and can even act as a weed barrier.

Drain rock is about as versatile as it gets!

Driveway Expert