A French drain that stops working, or never worked, is a common and frustrating problem. The yard is still wet, water collects over the drain, or the outlet never flows.
Most French drain failures come down to a few causes: a clogged pipe, a bad outlet, the wrong drain for the problem, or poor installation.
What you may be seeing
- Water standing over the drain line
- Yard still soggy after rain
- The outlet never flows
- Water bubbling out of the ground
- Sinkholes or depressions along the line
- The drain worked at first but slowly stopped
First question: does water come out of the outlet?
Find the outlet: a pop-up emitter, a curb outlet, a daylight pipe or a dry well. Run water into the drain or wait for rain. If nothing comes out, the drain is blocked or has no working outlet.
If no water reaches the outlet
The pipe is blocked, crushed, or the outlet is buried.
Possible causes:
- Silt-filled pipe or gravel
- Crushed or separated pipe
- Buried or blocked outlet
If water sits on top of the drain
Surface water isn't reaching the pipe, or the drain was meant for soil water, not surface water.
Possible causes:
- Sod or soil capping the gravel
- Clogged fabric
- Surface water needing a catch basin instead
If it worked at first and slowly failed
Gradual clogging is typical.
Possible causes:
- Silt migrating into the pipe without fabric
- Root intrusion
- Downspouts tied into the French drain bringing debris
What you can check yourself
Only check these safely and after rain has stopped. Do not dig near marked utilities, and do not go near electrical equipment that is standing in water.
- Locate the outlet and confirm it's open
- Run a hose into the drain or a cleanout and watch the outlet
- Look for depressions or wet lines along the drain
- Check whether downspouts are tied into it
- Note whether water sits on the surface or the soil is just soggy
Answer 20 quick questions → to get a preliminary drainage assessment.
What a drainage professional may evaluate
- Flow test
- Camera inspection
- Check pipe slope and outlet elevation
- Dig test sections to inspect gravel and fabric
- Design review: is a French drain the right solution?
Most common causes
Clogged pipe or gravel
Silt and fine soil fill the system over time.
Blocked outlet
The exit is buried, crushed or too high.
No slope
Water sits in the pipe.
Wrong solution
French drains handle soil water. Surface water may need catch basins.
Downspouts tied in
Roof debris and volume overwhelm the drain.
Roots
Roots enter perforations and joints.
Possible solutions
The right fix depends on where the water comes from, where it collects and where it can legally and physically go. These are the solutions most often considered:
Cleaning and jetting
Restore flow in an intact pipe.
Outlet repair
Uncover, lower or rebuild the discharge point.
Section rebuild
Replace clogged or crushed sections with new gravel, fabric and pipe.
Add surface drains
Catch basins for surface water the French drain can't take.
Separate downspouts
Move roof water to its own solid pipe.
Repair, adjust or rebuild?
If the pipe is intact and the outlet works, cleaning may restore it. If the gravel and fabric are packed with silt, or the slope is wrong, a rebuild is usually needed. If the drain was the wrong solution, redesign it around where the water actually comes from.
When to call a drainage professional
- The outlet never flows
- Water sits over the drain
- The drain failed within a few years
- You don't know where the outlet is
Frequently asked questions
How long should a French drain last?
A well-designed and well-installed French drain can last many years. Clogging from silt, roots or tied-in downspouts shortens its life.
Can a French drain be cleaned?
If the pipe is accessible and intact, it can often be flushed or jetted. Gravel that is packed with silt usually has to be replaced.
Why is water sitting on top of my French drain?
Surface water may not be able to reach the gravel because of sod, soil or clogged fabric, or the problem needs a surface drain instead.
Should downspouts connect to a French drain?
Generally no. Roof water should go in solid pipe to its own outlet.
Bottom line
Test the outlet, look inside the pipe, and make sure a French drain was the right solution. Then clean, repair or redesign.
This page is educational and does not replace an onsite evaluation. Conditions, codes and HOA rules vary by property.