How do you know if your French drain is clogged?

Author: Haley Bartoletti  |  Last update: Tuesday, September 30, 2025

Examine A Section of The Pipe Choose an area you think could be clogged and dig up the gravel in the trench. If you see standing water in the channel or water flooding over the pipe itself, the storm drain is clogged.

How to check if a French drain is clogged?

If you're uncertain where the drain starts, try looking at the highest point of your yard, since the design of the French drain is to help water run downhill. Step 2: Use a garden hose to run water down the French drain. If you notice the water backing up instead of running straight through, it's clogged.

How do you unclog a French drain?

Hose out the drain.

Run the water for 5 minutes, or until it is clear. If you have a pressure washer, use it to flush out the drain.

How often should a French drain be cleaned out?

Just like other types of drains, they are susceptible to clogging over time. Ideally, clean the French drain once every year. Test it by flooding the French drain to gauge its effectiveness when it comes to draining the excess water. First, you'll need to locate the ground-level access point of your French drain.

How do you test a French drain?

Testing the Drain

To test the condition of your French drain, you need to find the ground-level access point, which is usually an above-ground grate or the end-point of a downspout or an above-ground pipe. Running a hose down the pipe will show how effectively the drain is working.

How to unclog underground drains / french drains - Water-jetting

What happens when a French drain fails?

French drain problems can cause a fair bit of damage to your home, from small foundation cracks to severe flooding and mould. Keep an eye out for the tell-tale signs of broken or clogged weeping tile and get it repaired as soon as you can.

How much does it cost to clean a French drain?

If you have a severe clog and can't get it cleared or if you don't want to risk damaging the pipe with a sewer snake, then you should hire a professional French drain company near you to clean it. The average cost for drain cleaning runs between $150 and $340, with an average price of $240.

What is the lifespan of a French drain?

How long does a French drain last? A French drain should last at least 10 years, although it often has a lifespan of three or four decades when properly maintained. Sometimes sand or silt infiltrates the pipe over time, making it eventually useless.

Should I cover my French drain with dirt?

Fill the trench with topsoil and compact to completely cover the entire French drain system.

What is the average cost of putting in a French drain?

Installing a French drain costs $500 to $18,000, with a national average of $9,250. On average, you can expect to pay $10 to $100 per linear foot, or between $500 and $5,000 to have a 50-foot French drain installed.

How to clear a deep clogged drain?

A plunger can be effective for dislodging clogs near the drain opening. For deeper clogs, a drain snake or auger can reach and break up blockages inside the pipe. Hydro jetting kits, which use high-pressure water to clear pipes, are also available for more persistent clogs.

How do you clean a French press without clogging the drain?

Use a strainer inside.

Pour the coffee-water through a fine strainer that'll catch the majority of the grounds. Then toss them into the trash or outside.

Where not to put a French drain?

Clay soil has poor permeability, meaning it doesn't allow water to pass through easily. In such cases, the effectiveness of a French drain may be limited as the water may struggle to drain away from the area efficiently. French drains may not be suitable for areas with high water tables.

Can a French drain be unclogged?

In many cases, using a pressure washer is an effective way to unclog a French drain. That said, sometimes tree and plant roots, rocks, and even compacted mud create an obstruction that is too much for a pressure washer to handle.

How do I know if my underground drain is clogged?

If you notice water gushing back out from the drain pipe or leaking out from the seams on the adapter, that is a sign that there are clogs in your underground drain.

Should there be standing water in my French drain?

One of the most obvious signs that your French drain needs repair is standing water in and around the drain.

Do French drains need maintenance?

French drains can be a great way to direct rainwater runoff away from your foundation and septic system, but they require annual maintenance to keep them clear and working properly.

Where do you discharge a French drain?

French drains use gravity to move water away from the home and down through a pipe to an exit point. Exit points include the street, a grassy area with heavy sun exposure, or an existing underground drainage system.

How do I know if my French drain is working?

One of the simplest and most effective ways to determine the effectiveness of your French drain is through a regular visual inspection. Start by examining the visible portions of your drain such as the pipe outlets or the gravel trench. Look for signs of damage, blockage, or erosion around the area.

How deep are French drains buried?

French drain depth: About 8 inches to 2 feet deep should be sufficient for many water-diverting projects, though related systems, such as those built around foundations and sub-ground living spaces, as well as the bases of retaining walls, may be deeper.

What are the disadvantages of a French drain?

Disadvantages of French Drains

Another disadvantage of French drains is their potential to attract tree roots. The gravel or rock used in the system can provide a water source for trees, leading to the origins invading the drain. This can cause blockages and damage to the system.

Do plumbers put in French drains?

French drain installation is a service offered by a diverse range of professionals from landscapers to plumbers to foundation specialists. These professionals bring a varied skill set to the project, often integrating the drainage system seamlessly with other landscaping or construction work.

Can I do a French drain myself?

Connect with local French drain experts to help with your project. Installing a French drain yourself is possible but labor-intensive and time-consuming. Call 811 a week or two before you start your project to get your buried utility lines marked.

How much do plumbers charge to snake a drain?

Across the nation, if you were going to hire a professional plumber, the average amount you can expect to spend is approximately $250. However, if your clog is minor, plumbers may charge as little as $100. Of course, if your clog is substantially more complex, this could increase your costs to upwards of $400.

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