When it rains, does water run toward your house and foundation and cause it to flood? In this case, you may notice water pooling around the perimeter of your home and water leaking into your basement. Although re-grading the land around your house can prevent that from happening, the cost of professional grading is prohibitive — or it may be too labor-intensive for you to do by yourself.
Instead of regrading, you can install a French drain instead.
What is a French Drain?
A French drain is an underground drainage system that redirects water away from your home’s foundation. It consists of a trench filled with gravel and perforated piping to capture surface water and groundwater and channel it to a drainage outlet. A French drain around the perimeter of your house can be a great, inexpensive way to divert water runoff without having to regrade the entire yard.
Other common foundation drainage solutions, like a sump pump system, can also help keep water away from your foundation.
If you install it properly, a French drain creates a path of less resistance that rainwater will follow instead of pooling near your foundation.
How to Install a French Drain
French drain installation involves digging a 12- to 18-inch-deep channel that slopes downhill to route water toward a chosen exit point away from the house — but make sure you know the location of buried utility lines and pipes before digging.
You then put a 4- to 6-inch-diameter corrugated plastic pipe in the channel and fill the hole to the top with washed gravel. Water is lazy — it chooses the path of least resistance — so it will fall into your channels and be diverted before it reaches your foundation.
Digging a trench is necessary if you want to install a French drain.
A proper French drain has several key components:
- Channel or trench: Usually 12 to 18 inches deep and 6 to 12 inches across. This is where your pipe and gravel go.
- Drainage pipe: 4 to 6-inch flexible, perforated plastic pipe that fits in the trench to carry water away.
- Gravel backfill: Washed gravel around the pipe provides structural support and helps water permeate into the drain.
- Filter fabric: Lines the trench to prevent soil from clogging gravel.
- Outlet: Where the drain empties away from your house, such as a street gutter or downhill slope.
Proper slope and drainage planning are crucial — the trench must slope 1/8 to 1/4 inch per linear foot to keep water moving. If not sloped correctly, water can pool, and your drain won’t work effectively. Carefully plan where your drain will exit away from the house.
A French drain will require some heavy digging, as well as hauling and shoveling gravel. It also requires careful planning, as the channels must slope properly, or water will collect in them without running off. Once you’ve planned your design, you could enlist the help of friends, family, or even hired laborers to help with the physical work.
Want to install a French drain yourself? Read our guide: How to Install a French Drain in 7 Easy Steps
Should You Hire a Professional to Install a French Drain?
Hiring a professional landscape contractor to build the French drain for you is often a wise investment, even though it costs more than doing it yourself. They have the expertise to:
- Calculate proper slope and drainage
- Construct trench and pipe system correctly
- Evaluate drainage needs and design an effective system
- Locate buried utilities to avoid
- Select the right materials – pipe size, gravel type, filter fabric grade
- Troubleshoot problems if drainage is poor
Professional installation often costs $40 to $70 per linear foot, depending on trench depth and materials. However, it will likely be much less expensive than regrading the entire yard or building retaining walls.
Additional Considerations
In addition to the French drain, make sure any rainwater from your roof flows away from the foundation of your home — you’d be surprised how much water you can remove that way.
If you have gutters, extend the downspouts at least 5 to 10 feet away from the foundation or toward the French drain. Devices like rain chains can help divert water away from the house while also adding visual appeal. This prevents water from pooling near your foundation.
Further Information
If you’d like to learn more about French drains and other drainage solutions, here are some helpful videos and guides with step-by-step instructions and tips:
- Drainage Solutions (video)
- How to Create a French Drain (repair-home.com)
- How to Install French Drains for Yard Drainage (about.com)
- How to Keep Water from Damaging the Foundation of Your Home (video)
- Using a French Drain to Remove Standing Water in Your Yard (video)
So, Is Fixing Foundation Drainage With a French Drain a Good Solution?
Installing a French drain can be an excellent way to handle foundation drainage issues without undergoing major landscaping projects. French drains provide an affordable, focused solution that redirects water away from your home’s perimeter. However, proper planning and installation are critical for French drains to work correctly. Otherwise, you may still experience flooding or standing water.
For most homeowners, hiring a professional installer is worth the investment to ensure the job is done right — but French drains can also be a DIY project if you have the time and energy for digging trenches and hauling gravel.
Either way, a French drain is a smart first step before considering more complex and costly foundation waterproofing solutions. With proper gutter drainage, French drains can effectively capture surface runoff and protect your foundation.
FAQs About Fixing Foundation Drainage With a French Drain
How deep should a French drain be?
You should dig a French drain trench 12 to 18 inches deep to provide enough drainage capacity. The key is making sure the trench is below the level of your home’s foundation footing.
Can I install a French drain myself?
Yes, with proper planning, French drains can be DIY-friendly. However, they do require extensive digging, precise slope calculations, and careful pipe placement. Consider hiring a pro if DIY is too labor-intensive.
How long does a French drain last?
A properly installed French drain system can last for decades. Make sure you use quality materials like perforated PVC pipe, filter fabric, and washed gravel. Inspect your drains periodically for clogs or damage.
Where should the outlet for my French drain be?
Ideally, your French drain will outlet at least 10 feet away from your home, such as near a street gutter system or downhill slope. This safely diverts water away from your foundation.
Can I plant grass or landscaping over my French drain?
It’s best not to plant over a French drain trench. Roots can clog the system. Use rocks or gravel instead. But you can plant grass/landscaping near the edges of the trench.
Do I need to water or maintain my French drain?
French drains are passive systems that require little maintenance when installed properly. If anything, occasionally inspect the outlet and use a hose to flush out any debris that may be clogging the drain pipe.