French Drain: How To Build It The Right Way

30 Apr French Drain: How To Build It The Right Way

Drainage Issues in Minneapolis LawnHere in Minnesota, “lake life” is a way of life. Many people own a lake home and spend countless summer weekends fishing, swimming, and boating. Lakes are wonderful! Except when they’re in your lawn…

We get lots of calls about lakes or swamps forming in lawns. These kinds of issues can lead to loads of problems including foundation crumbling around your home, water leaking into your house, or diseases in your lawn. Beside the fact, it looks awful and makes your lawn less useful.

One of the most popular fix to these yard drainage problems is a french drain as part of a drainage system. A drainage system can have many different components including a french drain, drywell, closed tubing, catch basins, and pop up emitters. We’ll be discussing French Drains and Drywells and how to install them correctly in this blog post.



What’s your yard drainage problem?

French Drain ConstructionBefore starting to dig a trench or hauling in dirt to level off the ground, you want to figure out exactly what kind of drainage issues you’re having. There are three main kinds of drainage issues that occur in turf areas: swampy type of ground, water accumulating into a small lake, or a flowing small river.

Lake Forming

This is a critical problem, especially when it is formed by downspouts and near any house. Before taking care of any other problems, this needs to be addressed. These problems are often solved with two different methods. One method is to build up dirt near the house to angle the water away. Another method is to install catch basins and solid tubing. A catch basin is installed to collect all of the rain water from the downspouts which is then connect to solid tubing. The solid tubing moves the water to a pop up emitter where all of the water pushes out to a street or catch basin.

Swampy Ground

One of the tell tale signs of swampy ground is when you walk on the ground and some water pushes up around your shoe. This can last for days after a rain storm. The water builds up and stay in the ground for any number of reasons: the ground is super compact, there is lots of clay, the ground is angled differently, or any number of things. Swampy ground is often best solved by installing French Drains and/or Drywells. How they do this is discussed below.

Flowing River

Just like with the other two problems, this can be caused by a variety of reasons. Often it’s a combo of the two problems above. By fixing one or both of those problems, the rainy river will often go away. So catch basins and french drains can both be answers to this problem. It really depends on the other circumstances.

outdoor drainage edina mn



What is a French Drain and Drywell?

French Drain Diagram How To BuildWater follows the path of least resistance and a french drain is that path.  A french drain is a trench dug in the ground with a perforated tube and filled with gravel or loose rocks. The purpose is to take water from wet areas and disperse it in dry areas. The loose gravel and tubing with holes in it help facilitate that water movement. Swampy areas in a yard occur because there is too much water there so moving the water away and spreading it out corrects that problem. You can read about how to build them correctly below.

A drywell is a hole dug deep in the ground using a post hole digger or auger and filled with gravel. This a vertical version of a french drain. The gravel in the vertical hole allows the water to penetrate deep into ground and spread out in different areas. If you have the machinery (rather than elbow grease) these are super easy to install and can often be a quick fix to a swampy ground area.




How to Build  A French Drain Correctly

What You NeedFrench Drain How To

  • Trenching Shovel (or power trencher from rental company)
  • Perforated drain tubing with a fabric sock over it
  • Gravel (but not limestone, it turns to concrete)
  • Landscape fabric that allows water through
  • Post hole digger or auger
  • Catch Basins to allow water into the drains

First Step

The first step, and if you read everything above then you’ve already done it, is to make sure a french drain is the right answer to your problem and to make a plan. Having a professional come out and look at your property and assess what is going on is the best way to make sure you’re not wasting your time. But, if you haven’t read the info above, a french drain is often best with swampy ground. You want to plan out the trench before you start doing any digging. Know where you are starting (near the middle of the swampy area) and where you’re going to end (further away in a dry area of your lawn). You can even mark the areas with flags or sticks.

Second Step

Start digging. You want the trench to be at least 8″ deep. We would suggest digging it at least 8″ wide as well. A wider trench will allow the trench to last longer because it won’t collapse in. It also allows more room for water to pass down because, again, the point of a french drain is to get water from a wet area to a dry area. You can dig the trench by hand with a shovel (we LOVE trenching shovels) or you can rent a trencher from a rental company. We have done both methods depending on the length of the pipe that needs to be installed.

This is the time you want to install a drywell, if you’re going to. Just dig some deep holes with a post hole shovel or with an auger. Then make a sock with landscape fabric and fill it with gravel. Just drop the sock in the hole and you’re good.

When you’re finished digging, line the inside of the trench with landscape fabric that allows water to pass through (duh, haha). The fabric helps prevent some roots from getting into the drain and messing up the water flow. It also holds back the soil from encroaching into the gravel.

Third StepAggregate Surrounding French Drain

Fill in the bottom of the trench just a little bit with rock (1″ to 2″) and lay the perforated tube on top. MAKE SURE THE PERFORATION IS ON THE BOTTOM TOWARD THE ROCK. Also, you’ll want the perforated tubing to have a fabric “sock” around it. This stops roots from getting into tube as well dirt. The longer the tube can be free, the longer the system works correctly. Then, just mostly fill the trench with gravel and replace your grass and dirt. That’s it!


If you need some professional guidance or want our team to install an Outdoor Drainage System, please feel free to fill out a quote request or call us at 763-568-7251.