3 Ways How To Get Rid Of Flooding In Backyard

flooding patches in backyard with healthy green grass and a few brown trees in the distance

When the sun is shining, your backyard is perfect.  The lawn is green, and the flowers are in bloom.  But what happens when it rains?  If your backyard is like mine used to be, it floods.  Specifically in my case, it flooded my basement. Perhaps yours just pools water creating a mosquito habitat. Maybe the sheet flow from the rainstorm causes your mulch to wash away from your flower beds.  Whatever the case, in this article we will discuss how to get rid of flooding in backyard.

How To Get Rid Of Flooding In Backyard

First, it’s important to find out what the topography is in your backyard.  Often when a backyard is gently sloping, it can be just about impossible to tell by looking at it.  I am a landscape professional who has been designing peoples yards for over 20 years. Even I couldn’t see my backyard slope. 

On my property I assumed I just had a corner of the basement that would always get wet.  One day I took the laser level out of my truck, set it up and realized half the yard was sloping towards the house! Once you determine where your have a slope, you can begin to focus on how to level your backyard.

rain boots stomping into a puddle in backyard showing how to get rid of flooding in backyard

How To Get A Topographical Map Of Your Backyard

To understand your topography, you can hire a civil engineer or surveyor to do a topographical map of your yard.  This might be a good solution if you’re planning other landscape improvements and need to know how the slopes all work together.  Or, for less than the cost of hiring a civil engineer or surveyor you can buy a laser level and discover what the grade is doing on your own. You can also rent a laser level, but I always like a good excuse to buy a new tool.  

Best And Most Affordable Laser Levels

I have had good luck with my Bosch laser level. I’ve used it over the course of around ten years now, and it has never let me down.  It’s well made, but I take good care of my tools, so it’s hard to say how well it handles being abused.  There are other cheaper options out there now which would work just fine for a small backyard project.  They cost a fraction of the price of the Bosch.  For example, the Motovera laser level. This laser level will not be as accurate as the Bosch.  However, when doing site grading work, so long as you know which way is downhill, you’re in good shape.

How To Mitigate Water Flow And Stop Flooding With A Swale

Once you know which way is down, you can assess what’s actually going on in your backyard.  If you have pooling water, you already have a good idea of what the issue is. However, if you have a wet basement like I did, you just need to know which way to send the water to get it away from the house.  

Once you know how the yard is draining, you’re faced with mitigation methods.  First, you can build a swale, which is how I solved my backyard drainage problem.  Since the grade was minimal, I was able to dig a shallow and wide trench about 20 feet from the house to catch the surface water as it made it’s way toward the house. 

long white patch of rocks in backyard showing how to get rid of flooding in backyard with swale drainage system

Then I graded the earth between the swale and the house to drain toward the swale, away from the house.  The swale continued until I got to a lower portion of the yard, where it blended into the landscape.  This solved my wet basement issue.  

How To Get Rid Of Flooding In Backyard With French Drain

The next method for how to get rid of flooding in backyard works well if you have limited space.  Also, it works well if you wish to maintain a flatter looking lawn without a swale built into it. If you pitch the lawn toward a chosen line of a low point, then build a French drain under the line of low point, you will be able to drain most of the water away.

small patch of rocks in between old green grass with a light green french drain taking in water

How To Dig And Backfill The Trench

You start by digging a trench a 18” or more deep, and backfilling with 1 1/2” or 3/4” crushed stone with a perforated pipe approximately 6” above the bottom of the trench. Make sure the perforations of the pipe are facing down.  Also make sure the pipe is angled toward your drain location at 1/8” per foot or more.  This will take some pre-planning. We will talk more about your drainage location in a moment.

Backfill the perforated pipe with crushed stone and if you want it to work best, leave the top of the French drain crushed stone.  You can sometimes work this into the landscape as a feature, a stream bed, or otherwise to make it an attractive part of the yard.  If you must have grass, you can cover it over with filter fabric and put 6” of topsoil over the French drain with grass planted on top.  

You will want to add lawn drains if you put lawn over your French drain.  This will ensure water can find its way into the French drain during a heavy rainstorm.  

How To Plan For Drainage With A French Drain

The termination of the French drain can be accomplished in a few different ways.  If your yard has some slope to it, you may be able to let it ‘daylight’ and drain on its own.  You’ll want to check with local regulations however, as sometimes ‘daylighting’ subterranean drain systems is frowned upon.  If you can’t drain to daylight for whatever reason, you may find yourself in need of a dry well. 

A dry well is a concrete cistern without a bottom which may have perforated sides and a concrete lid.  The dry well is filled with rip rap (large crushed stone), and acts as a place for water to build up and slowly percolate into the surrounding soils.  

As you might guess, a dry well requires you to have soil which drains. It also requires the ground water table to not be above the dry well.  If you have a high water table, you may need to consider a sump pit which pumps the water to a storm drain (again, check with regulations!), or to a purpose built surface retention area to evaporate.

How To Stop Puddling Areas With A Dry Well

You might have an area that puddles whenever it rains, but then drains into the soil afterward. If so, you’ll want to build a dry well at the spot where the soil puddles and speed up the process.  You don’t need any piping to make this work. 

You simply install a drywall or two or three, depending on your situation. Then you can backfill with crushed stone and either leave a crushed stone area open to the air, or cover over with filter fabric, topsoil and grass with lawn drains down into the dry wells. You will find your lawn no longer puddles, and the mosquitoes no longer have the perfect habitat to wage war on your family.

backyard picture of an underground black drain pump showing how to get rid of flooding in backyard with a dry well

If you can’t bring a heavy concrete dry well into your yard, you might want to consider the Flo-Well system by NDS.  These are plastic dry wells which can be placed in series along your French drain to accomplish the same task as the concrete drywall without the need for as much crushed stone or excavation work.

How To Get Rid Of Flooding In Backyard Summary

Hopefully this has been a helpful review of how to get rid of flooding in your backyard. Without flooding concerns, your property will be far more usable. In fact, you’ll sleep easier knowing you no longer have risk of flooding whenever it rains.