What is Underground Drainage?

Mary McMahon

Underground drainage is water drainage which is routed underground, rather than along the surface. There are a number of reasons to choose underground drainage, and such systems need to be installed with care. People need to make sure that they drain to the correct location, and that they are installed with materials which are sturdy, and will be able to withstand incursions such as roots. Irrigation and drainage companies can design and install such systems for people who would prefer to leave things in the hands of experts.

In underground drainage systems, pipes often disperse water to storm drains.
In underground drainage systems, pipes often disperse water to storm drains.

Drainage is an ever present issue in any area where there is water. In some cases, the natural design of a property provides enough surface drainage that drainage is not a major problem. In other instances, people may notice pooling, soggy soil, and other signs of a drainage problem. Drainage problems need to be addressed because poor drainage can compromise the foundations of a home, damage plants in the garden, look unsightly, and make it difficult to walk around the garden or yard. Poor drainage can also contribute to erosion and other problems.

Mosquitoes might use underground drainage areas as a breeding ground.
Mosquitoes might use underground drainage areas as a breeding ground.

One option is to install a surface drainage system which collects water and routes it to storm drains, the street, or another suitable area. This can be unsightly, however, leading some people to prefer an underground drainage system. With underground drainage, a series of collection sites lead to underground pipes which dump out into a downhill location. Collection sites include downspouts from the gutters and grates in strategic low points around the yard or garden.

The pipes used for underground drainage need to be able to repel roots which could attempt to grow through them. Some people use a french drain system, with perforated pipes surrounded by gravel. This system allows water to quickly percolate through the gravel and into the pipes, allowing drainage to occur everywhere the pipes run, rather than collecting water at central points. This wicks subsurface water away quickly and efficiently.

Placing the outlet for a subsurface drainage system in the proper location is important. For people in urban areas, pipes should drain to storm drains or into the street, depending on local ordinances. It is important to avoid routing water into the yards of neighbors, and to avoid creating an outlet on the property itself. Residents of rural areas should try to place the outlet in a downhill location, taking some measures to prevent erosion such as putting a screen on the outlet to break up the water as it exits the drainage system.

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Discussion Comments


Roots are a bigger problem for underground drains than people realize. They can get through the smallest cracks and gaps and grow in them and expand them.

My dad installs underground drainage and sometimes his team have to fix them and clean them too. He has had to fix so many drains that were completely clogged by roots growing in them.

If the drains are made of good materials and installed correctly, this isn't a problem. That's why people need to work with professional companies that have a lot of experience with drainage.


Underground drainage is expensive. We have some issues with drainage on our property. After it rains heavily, the soil is soaked for days and just doesn't drain. It is affecting the vegetation negatively. The vegetation is basically dying because of too much water. We've been looking into various options for drainage. Underground drainage appears to be best option but it's going to cost us a lot.


Drainage is extremely important. Every year, in the news, we hear about people dying in severe floods around the world. The main causes is lack of proper drainage systems to prevent flooding. It's important for there to be storm drains that are capable of handling large volumes of water.

This is the responsibility of cities. It doesn't matter what kind of drains we have placed on our property. If the city doesn't have good storm drains, the issue of flooding can be inevitable.

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