French Drains

Photo of uncovered French Drain inside trench.French Drains are simply drainage trenches utilized for eliminating excess surface or groundwater from areas that are prone to saturated soils. These areas are generally located at the base of uphill slopes where surface water runs down from higher elevations and accumulates. Low lying areas of your yard are common to experience this issue as well. If not addressed, this accumulation of water has the ability to cause many issues. It is important to redirect this water away from your home in order to prevent excessive hydrostatic pressure that could possibly penetrate or otherwise damage your home’s foundation walls.


The French Drain’s primary purpose is to act as a channel to redirect water’s natural flow and conduct it to an area where it no longer has the opportunity to pose a threat to your home or cause problems in your yard. These drains are typically installed in the lowest spot of the problem area where it is able to intercept the excess water that accumulates, allows it to percolate down, and then channels it away.

3D diagram of French Drain, along with notations of related terminology.A trench is excavated between 6 to 8 inches wide and 8 to 12 inches deep, all depending on specific site conditions. Special attention is paid to ensure that the trench is sloping downwards at a rate of no less than 0.5%. This is crucial because gravity is basically doing the work of conducting the water away. A permeable landscape fabric is used to line the trench before clean, washed gravel is used to cover the bottom. A rigid perforated hollow pipe is then placed over the gravel with the perforations pointing towards the bottom. This will allow the pipe to vent up the water that seeps down into the trench and conduct it away. Depending on the expected volume of runoff, these drains can be installed utilizing multiple pipes. The pipe is then completely covered with more clean, washed gravel and the landscape fabric is wrapped over the top. The landscape fabric will prevent the surrounding soil from filtering through the gravel to the pipe which could eventually clog the system rendering it ineffective. The trench is then either filled the rest of the way with stone to create a nice landscaping feature or filled to a point a few inches below grade with stone and topped off with soil enabling the drain to be completely concealed.


Installed correctly, French Drains are simple yet very effective systems for the transportation of excess water safely away from your home or out of your yard to a more desirable location. This is a very affordable solution to an issue that could possibly cost you thousands in repairs later down the road.


At Preferred Basement Solutions, we are always ready to assess your specific issue and recommend the best possible solution. If excess water accumulating in your yard is causing problems, then a French Drain may be the perfect solution!