How to Install a French Drain: Step-by-Step Tutorial

Persistent standing water in your yard or near your home’s foundation can cause more than just muddy patches—it can lead to foundation cracks, mold growth, and even structural damage over time. Fortunately, there’s an effective and long-lasting solution: a French drain. This underground drainage system collects and redirects water away from trouble spots, helping maintain a dry, healthy landscape.

Installing a French drain is just one method of improving your property’s drainage. If you’re dealing with a broader water issue, be sure to check out our complete guide: 8 Ways to Improve Drainage Around Your House for additional solutions.

Whether you’re a DIY enthusiast or a homeowner trying to tackle drainage issues on a budget, this guide walks you through how to install a French drain, one manageable step at a time.

What is a French Drain and How Does It Work?

A French drain is a trench filled with gravel that contains a perforated pipe. Water naturally flows into the gravel-filled trench and enters the pipe through small holes. Gravity then carries the water away from your home to a designated drainage area. It’s especially useful for:

Diverting water from saturated lawns
Preventing basement or crawlspace flooding
Reducing soil erosion
Managing runoff near driveways and patios

Tools and Materials Needed

Before you start digging, gather the following items:

Shovel or trenching tool (rental trenchers save time on longer runs)
Wheelbarrow and garden rake
Tape measure and stakes with string
Landscape fabric (water-permeable)
Perforated drain pipe (with or without sock)
¾-inch clean gravel or crushed stone
Level or laser level
Utility knife or scissors
Soil tamper (optional but helpful)

Step 1: Identify and Evaluate the Drainage Problem

Walk your property after a heavy rain and observe where water collects. The starting point of your French drain should be the wettest area, and the endpoint should lead downhill or to a safe drainage location like:

A dry well
Rain garden
Storm drain
Gravel pit or sump pump

Make sure the drainage endpoint abides by local codes—some municipalities prohibit directing stormwater into streets or neighboring lots.

Step 2: Plan Your Drain Path and Grade

Use stakes and string to outline the drain path. For gravity to work, the trench must slope at least 1%—that’s 1 inch drop per 8–10 feet of trench. Check the slope using a level, laser, or builder’s line with a line level attached.

✅ Pro Tip: Avoid tree roots or buried utility lines—always call 811 (or your local utility marking service) before you dig.

Step 3: Dig the Trench

Dig a trench about 6 to 12 inches wide and 18 to 24 inches deep, depending on the water volume you’re handling. Keep the bottom smooth and maintain a consistent slope to ensure good drainage flow.

For shorter runs or tight spaces, you may want to dig manually using a shovel or post hole digger. Not sure how to dig effectively without machinery? Check out our guide on How to Dig a Fence Post Hole by Hand for detailed digging techniques that also apply to trenching projects.

Pile the excavated soil on a tarp for easy removal or reuse later.

Step 4: Line the Trench with Landscape Fabric

Line the trench with permeable landscape fabric, allowing for several inches of overlap on each side. This keeps sediment and soil from clogging the gravel and pipe over time, greatly extending the lifespan of your drain.

If you’re using pipe with a sock (pre-filtered), this step is still recommended to reduce long-term clogging.

Step 5: Pour in the Base Layer of Gravel

Add 2–3 inches of gravel to the bottom of the trench. Use a rake or your hands to level it out. This layer supports the pipe and improves initial drainage.

Step 6: Place the Drain Pipe

Lay the perforated pipe in the center of the trench with the holes facing downward. Why? Because water enters from the bottom where saturation happens first. Ensure the pipe follows the trench’s slope and connects securely if using multiple lengths.

✅ Optional: Secure the pipe using landscape pins to prevent shifting while filling.

Step 7: Cover the Pipe with More Gravel

Backfill the trench with gravel until it’s about 2–3 inches below ground level. This leaves space to cover the drain with soil or sod. Make sure the gravel layer is even and firmly tamped down (use your foot or a tamper tool).

Step 8: Wrap the Fabric Over the Gravel

Fold the overlapping fabric ends over the top of the gravel. This creates a barrier that prevents soil intrusion but allows water to pass through freely. Think of it as a filter wrap that ensures your system stays functional for years.

Step 9: Finish with Soil, Mulch, or Sod

Cover the fabric with soil and replant grass if the drain is installed in a lawn. For garden beds or hardscape areas, you can top with mulch, river rocks, or decorative gravel. Just make sure the finished surface still slopes slightly away from your home.

Bonus: Where to Direct the Water

If you’re unsure where to redirect the collected water, here are a few options:

Dry Well: An underground basin that slowly disperses water into the surrounding soil.
Rain Garden: A shallow landscaped basin with water-loving plants.
Sump Basin with Pump: Useful if your yard is flat and water needs help moving out.

Conclusion

Installing a French drain is one of the most practical solutions for water problems plaguing lawns, foundations, and low-lying areas. With some planning, the right materials, and a weekend’s effort, you can protect your landscape and home from costly water damage. Whether you’re a DIY beginner or experienced homeowner, this system is a reliable investment in the longevity and health of your property. For more detailed information and tailored advice, visit our page on digging. For support on your next hole digging and trenching labor project, please feel free to reach out through our contact form, and our team will be happy to help.

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