Average Cost Estimate
Installing a french drain around the foundation of your home is an affordable and effective way to divert water away from the house and ensure that your basement or crawl space stays dry, especially if you don’t have gutters installed on your home. The concept of a french drain is simple: instead of water soaking into the ground up against your foundation, you divert the water away from the home using a perforated pipe under the soil. One of the most common causes of a leaky basement is rain water that soaks into the soil and moisture seeps through basement walls and even up through the floor. This can be avoided with an exterior french drain, which is much simpler and cheaper to install than an interior french drain. A french drain is also great if your yard collects a lot of moisture, or if you see areas that tend to puddle up after rain.
This page of Costimates focuses on the cost to install a french drain along the outside of your home. We’ll cover the price of the supplies needed, the amount of time that it takes to install a french drain and show you what you may expect to pay if you decide to hire a local professional to do the job. Finally, we’ll discuss permits and/or inspections, as well as sharing a cost comparison of what other leading websites show a french drain cost. At the end, we have a section where homeowners and pro’s share what they paid or charged for french drain installation. If you’ve been quoted or recently had the project completed, we hope you’ll share your cost as well.
Product and Supplies Cost Details
Exterior French Drain Price Factors
An exterior french drain will require only a few supplies (and a lot of digging). The following factors should be considered when pricing out your french drain:
- Linear Distance – The cost of a french drain corresponds directly to how long the drain needs to be. The length of the perimeter around your home and the distance to a drainage area will determine how many linear feet you will need to buy supplies for.
- Landscaping – When installing an exterior french drain, you will be digging a drench several feet deep depending on the depth of your foundation and 1.5-2.5 feet wide around the perimeter of your home. This means you may need to factor in the cost of replacing any obstructions like fences, gardens, sidewalks and driveways, landscaping features or shrubs, as well as new grass seed to cover the area once it is filled back in.
Cost of Installation Supplies
Once you have determined the linear distance you need to cover you can use the prices below to determine the overall cost to install a french drain. These prices may vary based on your local area but should give you a good overall indication of how much you will need to spend:
- $60 – $70 per 100 feet | 4″ perforated drain pipe – Drainage pipe is laid in the trench on a bed of stone, at a slight drainage angle that diverts runoff water away from the area.
- $20 per cubic foot | Drainage gravel – Gravel is used to fill the trench below and above your drain pipe. You’ll use approximately 2 square feet of gravel per linear foot of trench.
- $20 – $25 per 100 feet | Landscape fabric – Landscape fabric is placed into the trench first and wrapped over your drain pipe to prevent clogging. You can also purchase perforated drain pipe that is pre-wrapped with the cloth, but at a higher cost. Regardless, you need the landscape cloth on top of the trench as well.
- $5-10 | Plastic couplers to connect pieces of drain pipe.
- $150 – $200 per day | Trencher rental. (Optional, but recommended)
Permits, Inspection, and Exterior French Drain Installation Cost
Since installing a french drain will require extensive digging and possibly connecting to a city sewage drain, you may need a permit. Check your local laws on drainage system installation to determine if this project will require a permit or inspection.
- $50 – $200 ea. | Local permits (if required).
- $0 – $75 | Before digging the trench for your french drain you will need to call 811 to have your utility lines marked so that you do not hit any underground pipes or wires. Most areas of the US provide this service for free.
Installation Labor Factors
The cost to install a french drain is mostly reliant on the amount of labor involved. You should take these factors into consideration when determining your overall cost:
- Length and depth of drain – The more you have to dig, the more time it will take and the more you’ll need to spend on labor. If you are doing the project yourself, you should consider renting a trencher to save yourself hours of time.
- Obstructions – If you have gardens, patios, sidewalks, decks or other obstructions the cost of installation will increase. The project is always cheapest when you have a clear path to dig your trench.
Average Outdoor French Drain Installation Cost
- $25 per linear foot – Estimated cost to hire a professional to install an exterior french drain.
Completed Installation Time
- 6 – 8 Hours | A simple french drain installation can be done in one day by a team of professional landscapers barring any complications.
- 1 – 2 Days | If you rent a trencher and do the project yourself, you can expect it to take up most of your weekend.
- 3 – 4 Days | If you are planning on digging the entire trench by yourself using a shovel.
DIY or Hire a Pro
Digging and installing your own french drain system is not a highly skilled project, but it is hard work and labor intensive. If you choose to do your own, you need to be aware of how to use a level and stake a grade. How to drive a wheelbarrow, and be good friends with your shovel and iron rake. Renting a ditch trencher is the best way to go if you choose to do this on your own. And… get a few friends to help out, you’ll need it!
- Plan for a couple days of very labor filled manual work.
- Rent a Trencher or hire a Pro to save the headaches.
- ALWAYS call for a dig safe underground utility locator.
- Line up several friends to help out – you’ll need it!
I’ve put a french drain in both interior and exterior around a home to divert water and keep the basement and foundation dry. I’ve done this for both myself, and when I worked for a landscaping company back in my younger days. It’s never been an easy job and requires a lot of manual labor and wheelbarrow driving. Today, I would hire someone to do this versus doing it myself. 20 years ago… that’s a different story.
Installed Costs from Around the Web
Compare french drain costs around the web from other websites and companies who do the work.