How Does A Drain Tile System Work?

drain pipe in a ditch.
drain pipe in a ditch.

If your home has a wet basement, a drain tile system can probably solve your problem because it takes water and moves it away from your home’s foundation. Applications include basement waterproofing, crawl space waterproofing, and yard drainage.

Other names for this highly effective basement drainage and waterproofing solution include weeping tile, French drain, drainage tile, perimeter drain, and foundation drain.

In this article, we’re going to go over the basics of how drain tiles work, the difference between an interior and exterior drain tile system, types of drain tile pipes, cost, and finish up by giving you a list of the most common signs of foundation drainage problems.

How Does A Drain Tile System Work

What is a drain tile system?

A drainage tile system is an interior or exterior waterproofing solution that stops water from pooling near your foundation by taking excess moisture at the foundation’s base and redirecting it to a sump pump that carries it away from the structure. However, if there’s a good downslope, gravity might be able to handle this without using a sump pump.

The term “drain tile” is a misnomer since no tiles are involved, just rigid or flexible perforated pipe. Drain tile can be installed either outside, along the foundation’s perimeter, or inside, under the basement floor. Contractors can also install it in other areas that are prone to water pooling.

If a home has a lot of groundwater beneath the floor – from a natural spring, for example – a drain-tile grid under the floor – and with multiple pumps – will be able to keep up with the amount of water leaching through the soil.

Newer homes built with a drain tile system usually have it installed at least around the outside of the foundation. A drain tile system is easy to install during the construction of the house and definitely worth it. If you’re buying a home, look for one with a drain tile system.

Of course, drain tile can also be installed in an existing home, either inside or outside. However, installing it outside of an existing home will mean excavation down to the foundation’s footer. Installing it inside means using a jackhammer on the basement floor to break up the concrete. Therefore, a drain tile system is a major construction project that should only be handled by professionals.

Check out more about: The Importance of Proper Foundation Drainage

Drain tile installation: Interior vs. exterior

There are two types of drain tile systems: interior and exterior. Interior drain tile systems are installed beneath the basement floor/slab, while exterior drain tile systems are installed around the home’s outside perimeter.

Fortunately, regulations in the US now mandate a drain tile install in homes with basements and crawl spaces unless the structure sits atop soil that drains easily. Therefore, if your home is relatively new, it probably already has at least an exterior drain tile system installed.

Interior drain tile

Interior drain tile systems are installed beneath the basement floor/slab. They are often installed in older homes that don’t have an external drain tile system. However, interior drain tile systems are installed in new homes as well.

The procedure involves first moving everything out of the basement, including any floor coverings. The foundation repair contractor then uses a jackhammer to break up the floor. After that, a trench is dug around the basement’s inside perimeter, along with a sump pit. The drain tile pipe – either rigid or flexible – is placed in the trench along with gravel, and then the floor is replaced. The new drain tile system will now channel water into the sump pit. A sump pump will take that water and pump it out and away from the home.

At Epp Foundation Repair, we’ve never had an interior basement drain tile system clog. However, if necessary, a repair contractor can access the drain tile system via the sump pit. Cleanouts can be installed, but customers are usually finishing the floor and don’t want them.

Exterior drain tile

In an exterior drain tile system, the perforated pipe is installed around the home’s perimeter at the footer level. Today, most new homes are built with an exterior drain tile system. However, they can also be installed in older, existing homes, but it’s a lot of work.

The process of installing an exterior drain tile system in an existing home involves excavating down to the footer, digging a trench along the footer, and then a sump pit, if necessary. The perforated pipe goes into the trench and is covered with gravel and a special, porous fabric designed to keep soil out of the pipe. Finally, the pipe is covered with soil, and the excavated dirt is replaced. Any excess water in the soil will now either drain away from the foundation via gravity or drain into the sump pit and then get expelled by a sump pump.

While both interior and exterior drain tile systems are highly effective basement waterproofing solutions, they are also a lot of work. Don’t attempt this project on your own. Call a professional.

Two types of drain tile pipes: rigid PVC vs. corrugated flexible

There are two types of pipe used in a drain tile system: rigid PVC and corrugated flexible. Both are usually around 4 inches in diameter when used for drainage around residential homes.

Rigid PVC pipe

Rigid PVC pipe has small holes on one side. When the pipe is placed in the trench with the holes facing downward, water gets into the pipe through the holes. Because the pipe is rigid, it needs corner fittings for any direction changes.

Corrugated flexible pipe

Corrugated flexible pipe has small slits all over the pipe. Water can enter the pipe from all sides, but the slits are small enough to keep out soil. Corrugated pipe is less expensive than PVC pipe and easily bends around corners. It’s also highly durable in all temperature extremes, hot or cold.

How does a drain tile system work?

Drain tile takes advantage of the fact that water always takes the path of least resistance. Water flows into the pipe via the holes or slits, and from there, it’s released somewhere above ground. If your property isn’t sloped enough (should be at least 1/4 inch of slope per foot), the water will flow into a sump pit. From there, a sump pump will expel it away from your home’s foundation.

The idea behind a drain tile system is to make sure water doesn’t build up in the soil under and around your home’s foundation. It takes excess moisture in the ground and channels it away from the foundation.

Read also: Common Causes of Foundation Settlement

How much does a drain tile system cost?

The cost of a drain tile system can vary considerably. Factors that go into the cost include whether the system is interior or exterior, rigid or flexible pipe, and whether it’s being installed in a house under construction or in an existing home.

If you DIY, it will cost less. However, we don’t recommend it. Installing a drain tile system in an existing home is a major construction project, and as such, it should be left to the pros.

The only way to know for sure how much it will cost to have a professional install a drain tile system is to call an experienced contractor and ask for an inspection and estimate. Most contractors will do the inspection for free.

We serve Lincoln, Omaha, Grand Island, Kearney, NE and more with foundation repair, basement waterproofing, concrete leveling, crawl space encapsulation services. Call us to schedule an inspection and receive an estimate based on your needs.


Dave Epp

Dave is the President at Epp Foundation Repair with over 27 years of experience in the industry. Dave has worked on thousands of foundation, basement, concrete, and crawl space repair projects since 1993. Dave is involved in several civic and church organizations and enjoys coaching youth sports, mainly football, golfing, and elk hunting.



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