Cleaning a French Drain: Your Handy Guide

With a little elbow grease, your French drain can be as fresh as a daisy.

A child running through a puddle from a French drain cleaning.
Image: Greggory DiSalvo/getty

Key Takeaways

  • To clean your French drain, you'll need to locate it, clear surrounding debris, inspect the drainpipe and flush the drain, use a pressure washer or drain snake for clogs, remove sediment, and rinse thoroughly.
    Scroll to: Step-by-Step Guide to French Drain Cleaning
  • To clean your drain less frequently, consider installing a grate or filter, cleaning the drain regularly, or monitoring water flow.
    Scroll to: French Drain Cleaning and Maintenance Tips

French drains can be a godsend for homeowners battling waterlogging issues. They divert excess water away from your property. And that diversion prevents soggy lawns, flooded basements, foundation damage, and wet shoes. However, to keep your French drain working properly and prevent clogs, you should regularly maintain it. Here's how to clean a French drain to protect your property and keep your toes dry.

French Drain Systems 101

A French drain is made up of a perforated pipe surrounded by gravel or rock and buried underground. It will cause excess water that has accumulated to seep into the perforated pipe to reroute. So, the water will flow from your property. And that will help prevent waterlogging your green, green grass, basement, or wherever you've installed the drain.

How Do French Drains Clog?

So, what causes a French drain to clog? Soil or clay may have built up in the pipe because the drain isn't filtering mud and other debris. Or tree roots may be causing a malfunction. To avoid these problems, test your French drain at least annually. Be aware that if you've neglected your French drain for a while, it may not perform well.

Signs Your French Drain Needs Cleaning

Cleaning your French drain regularly can help it work effectively and minimize chances of flooding. To detect the need for cleaning, watch for these signs.

Stagnant Water

The telltale sign of a clogged French drain is flooding or waterlogging. Your yard may be excessively wet and muddy or areas of your lawn may be consistently soggy or waterlogged. Another possibility: Water draining slowly from the area surrounding the French drain may show partial blockage.

Foul Odors

Stagnant water trapped by a clogged French drain can contribute to mold and mildew growth. And that can produce musty, unpleasant odors. If you smell mold or mildew near the drain, the system may not be draining properly.

Damp Basement

Some French drains aren't designed to direct water from the main home. But if yours was designed that way, your basement walls may feel wet or damp when the drain is malfunctioning. If you notice dampness, leaks, or flooding in your basement, the French drain may not be working correctly and need cleaning.

A graphic asking "What's Clogging Your French Drain?" and providing a few things like plant matter, tree roots, small pebbles, and silt or clay buildup.
Image: HouseLogic

Three Ways to Clean Your French Drain

When you need to declog and clear debris from the drain, you can choose from these tools:

  • Garden hose: You can easily flush out mud or silt in the French drain if it hasn't solidified. The water from the hose is enough to do the trick.
  • Pressure washer: A pressure washer shoots a concentrated stream of water at the buildup. And that can help dislodge rocks, debris, and anything that shouldn’t be there.
  • Electric snake: You can use an electric sewer snake to easily remove rocks, plant roots, and tightly compacted mud in a French drain. This tool, sometimes called a drain snake or auger, has a long cable with a claw that helps break up clogs.

Step-by-Step Guide to French Drain Cleaning

To clean your French drain, follow these eight steps in the process:

  1. Locate the drain: Find the French drain on your property. Look for the gravel-filled trench and identify where the drainpipe enters. Some drains may feature an above-ground grate.
  2. Clear surrounding debris: Use a shovel or garden rake to remove leaves, branches, or soil covering the trench.
  3. Inspect the drainpipe: Examine the perforated pipe for signs of blockage or damage. Use a flashlight to check inside the pipe for sediment buildup or obstructions.
  4. Flush the drain: Use your garden hose to run water into the French drain. If the water backs up, you may need more power to dissolve the clog.
  5. Use a pressure washer: Attach a pressure washer to a garden hose and insert it into the opening of the French drain. Turn on the pressure washer and feed the hose through the drainpipe. This will flush out debris and sediment as you go. Repeat this process from the opposite end of the drain to thoroughly clean the drainpipe. If a backup still exists, use a drain snake.
    Tip: When using a pressure washer, stay safe. Stand at the side, not the front, of the drain opening and hold the washer at an angle so water won't forcefully splash on you.
  6. Use an auger or drain snake: If you find stubborn clogs within the drainpipe, use a drain snake to break them apart. Insert the snake into the pipe and rotate it clockwise to dislodge the blockage.
  7. Remove sediment and debris: Use a shovel or garden trowel to scoop out sediment or debris that has piled up in the trench.
  8. Rinse and repeat if necessary: Once you've cleared the drainpipe and trench, rinse the area to flush out remaining debris. Check the drain again to see if it’s free from obstructions.

If none of these methods work for you, contact a professional plumber or drain cleaner for help.

French Drain Cleaning and Maintenance Tips

To clean you drain less frequently, follow these maintenance tips:

  • Install a grate or filter: Place it over the entrance of the drainpipe to prevent large debris from entering the system.
  • Clean the drain regularly: Use a garden hose to flush out the French drain monthly. This may help prevent clogs. If you live in freezing climate, install your drain below the frost line so it works year-round. The frost line -- also called the frost depth or freezing depth -- is the maximum ground depth at which soil freezes.
  • Monitor water flow: During heavy rainfall, monitor the water flow around your property and quickly address drainage issues.

The Last Word on French Drain Cleaning

Maintaining a clean and clear French drain can protect your property from water damage. On top of that, it can preserve your property's structural integrity and prevent a swampy yard or basement. Ongoing maintenance is key. That means you should regularly inspect your French drain, promptly eliminate blockages, and seek professional assistance when needed.

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