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Installing Subsurface Drainage Systems

Soggy yards combined with hard rains can often lead to a cracked foundation or constant water in a crawl space. Installing a subsurface drainage system can dry out the yard and prevent further damage to the home’s foundation. Here are some drainage options for a water logged yard.

Trench Drain

This is an easy and popular way to redirect water away from the home and into a safer location. In some cases, this type of trench system can run up to 100 feet long. Here’s how to complete this easy drainage system.


The trench should run parallel with the ground and be built on the high side of the property. When completed, the drain pipe should stick out like the entrance to a mine shaft. Dig a six-inch wide trench about 2 feet deep. Add two inches of gravel on the bottom of the trench and then place the drain pipe over the top. Cover the drain with additional gravel and add loose dirt up to an inch of ground level. Then hide the drain with sod or soil and you’re done. The system relies on gravity and perforated drain piping to deliver water away from the home or garage.

Linear French Drain

This is a buried pipe and drainage system that traps and redirects water before it can enter the home. This type of drain can solve a negative slope issue in the landscaping and block water coming from the neighbor’s yard. When homes are built on hillsides or mountainous terrain, excess water can run right into the house below. These drains are effective in diverting that type of hydrology.


To construct a linear French drain, dig a trench that’s about 2 feet deep and six inches wide. This drain needs to span any area that’s spongy or saturated. Place 4 inches of gravel on the bottom of the trench. Then place a perforated drain pipe over the gravel, and on top of that, layer in another 4 inches of gravel. You should still have about a half foot of space to work with. Place straw in that gap; this will act as silt filter. Finish the drain off with one more layer of white gravel and place soil over the top. The drain should exit away from the home’s foundation.

Downspout Pipes

This drain system takes the rainwater directly from the roof and discharges it safely away from the house. It’s recommended that the underground piping system be laid in sand or gravel, as this helps prevent broken lines. Some builders bury the drainage pipes near the foundation, which may result in water seeping back into the home. Make sure the drain exits at least 5 to 6 feet clear of the foundation.


Start where the water should be discharged and work your way back to the house. The trench doesn’t have to be deep, 16 inches is adequate. It should follow the contouring of the ground and then use top soil or sod to cover the piping.

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