The average French drain cost is $5,000, but your actual cost could be as low as $500 or as much as $18,000. This depends on the type of French drain, its location, and how much area in your yard you need to drain.
Factors in Calculating French Drain Costs
Several factors influence the cost of installing a French drain, including the depth and length of the drain and the materials used. To determine the best French drain for your yard and budget, assess the costs before you start installing one.
Depth and Length of the Drain
The depth and length are the most significant determiners of cost when it comes to installing a French drain.
Shallow vs. deep drains
Generally, the deeper your French drain, the more it will cost per linear foot. Shallow drains take less time to install and require fewer materials.
Most French drains are 8 inches to 2 feet deep. The depth of your French drain system will depend on factors like your ground type, nearby utilities, and other related drainage systems you’re tying into.
Drainage path and total linear feet
The average cost of French drains per linear foot varies widely. Depending on the location and type, installing a French drain pipe can cost anywhere from $10 to $100 per linear foot.
- Exterior French drains cost about $10 to $65 per linear foot.
- Interior French drains cost about $40 to $100 per linear foot.
Materials Used
The type of materials used is another major factor in determining the overall cost of your French drain project.
Type of gravel or stone
The type of gravel or stone you use makes a significant difference in the cost of installing a French drain. River rock is the most common drainage material used, but the cost of river rock varies depending on the type you choose.
The best stone for French drains is a natural river rock about ½ to ¾ inches in diameter. If you use anything smaller, the water won’t drain through it as easily.
Quality of perforated pipe
There are a few different types of French drain pipes to choose from.
- PVC pipe–For small backyard French drains, costs about $4 to $6 per linear foot
- Corrugated pipe–Lightweight and easy to bend, costs about $2 to $8 per linear foot
- Perforated drain pipe–Strong and holds more water than PVC pipe, costs about $4 to $10 per linear foot
Labor and Complexity
When calculating the labor for your French drain installation, consider the soil type, excavation challenges, and integration with existing landscaping.
Soils that require French drains are compact and difficult to dig in, which is why standing water is an issue, and a French drain is required to begin with. However, when building a French drain, you may run into other excavation challenges beyond difficult soil types.
With exterior projects, things like tree roots can cause damage and large rocks can be problematic, causing your project to take longer than expected.
When installing interior French drains, working in crawl spaces and basements makes your project more complex, increasing labor costs. The cost of interior French drains in basements is typically higher due to the increased labor costs associated with digging through a concrete floor.
Additional Costs and Considerations
The French drain system cost depends on several other factors, including landscaping, permits, and drainage accessories.
Landscape Restoration
Installing an exterior French drain is disruptive to your landscape. You’ll need to add the cost of restoring your landscape to the overall French drain system cost.
Integration with existing landscaping
Whether you’re integrating a new French drain with an existing one or tying it into your current landscaping, you may have to maneuver around obstacles, which will take longer and increase labor costs. You must also consider the cost of repairing your current landscaping so it all blends together seamlessly.
Replanting grass or gardens
Replanting grass or flower beds can add to the cost of a French drain. On average, it costs about $0.10 to $0.20 per square foot to plant grass. The cost per square foot to plant a flower bed is $4 to $12, depending on the materials and plants you use.
Hardscape repairs or replacements
Sometimes, you must put a French drain in a location that requires moving or repairing hardscaping features, including patios, retaining walls, and sidewalks. Each situation is different, but it’s an important consideration when choosing where to locate your French drain.
Permits and Inspections
Do you need a permit to install a French drain? It depends on where you live, but many municipalities require a permit for French drain installations.
Municipal permits
Municipalities have varying rules about permit requirements for French drains. You may not need a permit if your drain doesn’t change the flow of water to or from your property. However, if you’re tying into a municipal stormwater system, you will have to get one.
Cost of potential inspections
Whether or not a permit is required, you may need regular inspections for your French drain system. Contact a plumber or landscaping professional and expect to pay about $100 to $200 per hour for inspections, depending on where you live.
Drainage Accessories
French drains can come in the form of basic drains made with pipes and gravel, or they can be a little more sophisticated. Consider the cost of these drainage accessories when determining what will work best for your property.
Here are a few different types of drainage accessories you might use in a French drain system:
- Catch basins–As their name implies, catch basins collect water, which is then pumped to another location.
- Sump pumps–Used to pump water out of a catch basin or basement.
- Pop-up emitters–Connect to PVC drain pipe and open when the pressure builds, then close again when the flow is lessened.
- Slim channel drains and grilles–Used in concrete basement floors or driveways to allow water to flow through.
- Gutter downspout extenders–Used to divert rainwater away from your home.
French Drain Costs by Type and Size
When it comes to French drains, the most significant price fluctuations are due to their type and size. Take a look at the cost difference between interior and exterior drains and explore some figures to help you calculate your drain project cost.
Interior vs. Exterior French Drains
Interior French drains are standard solutions for basements and crawlspaces. French drains are a good long-term solution for wet basements, and while they cost more than exterior drains, they will help keep your basement dry.
People often use exterior drains to protect their basements or foundations. They also commonly use them for yard and garden areas. If you have standing water in part of your yard, a French drain system can help alleviate the problem so that you can grow an attractive lawn in that area.
Standing water issues not only cause problems with your lawn and garden, but they can attract mosquitoes, snakes, and other pests.
Small-Scale Drains (up to 50 feet)
Small-scale drains up to 50 feet cost between $500 and $5,000 to install.
Medium Drains (50-150 feet)
The cost of a medium-sized French drain in your basement or crawl space is $2,000 to $15,000. An exterior drain of the same size will start at about $2,000.
Large Drains (150+ feet)
Large interior French drains over 150 feet cost $15,000 or more. To have one installed in your yard, a large French drain system will cost about $6,000 to $18,000.
When Do I Need a French Drain?
Look for these signs to determine if you need a French drain, or if you’re considering new construction on your property, take a proactive approach towards drainage issues.
Signs of Drainage Issues
You may need a French drain if you notice any of the following drainage issues in your yard:
- Water accumulation in your yard or basement
- Mold or dampness in your home
- Standing water on your lawn
- Irregular lawn growth
- Spongy areas in your yard
- Cracks in your home’s foundation
Proactive Installations
If you’re constructing a new building or hardscaping project, such as a driveway or retaining wall, it’s a good idea to install a French drain as a proactive measure to avoid or control erosion or get rid of standing water.
Buildings change how the soil absorbs rainwater, and the concentration of water from the roof pouring into one spot in your yard can cause foundation and drainage issues if you don’t have a plan.
DIY French Drain Costs vs. Hiring a Professional
French drains are DIY-friendly projects, but there are still advantages to hiring a professional, especially for large-scale installations.
DIY Material and Equipment Costs
Here are the materials and equipment you need to install a French drain:
| Materials and equipment | Cost |
| ½ to ¾ inch washed gravel | $25 to $50 per ton |
| Landscape fabric | $0.45 to $0.80 per square foot |
| Drain pipe and fittings | $2 to $10 per linear foot |
| Trencher rental | $85 to $300 per day |
You’ll also need a shovel, wheelbarrow, and work gear. Renting equipment is more cost-effective for DIYers than purchasing it.
Advantages of Contracting a Specialist
Installing French drains is hard work, and while you can save money doing it yourself, it’s labor-intensive and sometimes requires a professional’s specialized knowledge and experience.
Hiring a professional has distinct advantages, especially if your installation requires a permit because professionals can help you draw a plan and submit the permit application.
Another advantage of hiring a professional is that they get price breaks on materials by purchasing them in bulk. Many of them own the necessary equipment, including trenchers and hauling equipment, which saves time and money.
How to Save Money on French Drain Installation Costs
Are you installing a new French drain? Check out these money-saving tips before you start.
Optimal season for installation–Installing a French drain is much easier and less expensive during the fall. Install your drain before the ground freezes, but after it’s had a chance to dry all summer.
Group discounts in communities or HOAs–If you’re part of an HOA, always check to see if you qualify for any group discounts. Or, you can combine services with your neighbors to get a better rate.
Regular maintenance to avoid reinstallation–You should factor replacement costs into your design and maintenance plan. While you may have to pay more upfront, you won’t have to worry about reinstallation for decades.
Leveraging local supplier relationships–If you use a regular landscape materials supplier, ask them to help you find an inexpensive source of rock for your French drain.
FAQs About French Drain Costs
How do I determine the ideal depth for my French drain?
Ideally, most French drains are 18 to 24 inches deep, but every situation differs. Soil type, existing drainage systems, landscaping features, and underground utilities will determine the ideal depth for your French drain.
What are the long-term maintenance costs associated with French drains?
Most French drain systems are relatively maintenance-free. You may need to use a plumber’s snake to remove leaves and debris, and if it becomes really plugged, hire a sewer and drain service to restore it for you.
Can you integrate a French drain with a rainwater harvesting system?’
With a rainwater harvesting system, a single roof can produce hundreds of gallons of rainwater in a single rainfall. That’s often more water than you can use or store at one time. French drains are an ideal way to deal with the overflow.
How long does a French drain typically last before requiring replacement?
French drains usually last 30 to 40 years if correctly installed and maintained. Not all French drains stand the test of time. However, professional installations, followed by periodic inspections and cleaning, will ensure your French drain has a longer lifespan.
Does the type of soil in my yard affect the cost of installation?
Some soil types are harder to work with than others. When it takes longer to dig a trench, the cost of a French drain is higher. Heavily compacted clay soils don’t drain well and are one of the hardest to dig.
