Moisture, mold & pests

French drain not working, yard staying flooded

A French drain that no longer moves water usually has a clogged pipe, a crushed section, or was never sloped correctly, and the yard pooling defeats its whole purpose.

Difficulty
Moderate
Time
1–3 hours to diagnose
DIY cost
$0–$50
Pro cost
$500–$3000

Symptoms

  • Standing water in the yard that used to drain, now doesn't
  • Water pooling near or over the drain's gravel line
  • No water visible exiting at the drain's outlet point

Likely causes

  • CommonClogged perforated pipe from sediment or rootsFine soil or roots can work into the pipe's perforations and gradually block flow over years.
  • CommonOutlet blocked or buriedThe discharge end can get covered by soil, mulch, or debris, backing up the whole system.
  • PossiblePipe crushed or sloped incorrectlySettling, vehicle traffic, or a poor original installation can create a low spot or crush point that traps water.

What to do

  1. Find and check the drain's outlet point for burial, blockage, or debris and clear it if needed.
  2. Run a hose into the inlet or a cleanout (if present) to see whether water exits at the outlet, which tells you if the pipe is at least partially clear.
  3. If accessible, use a plumbing snake or a jetting attachment to clear sediment or root intrusion from the pipe.
  4. Dig a small test hole along the drain's route to check that the gravel isn't fully clogged with fine silt, which happens over many years without fabric wrap.
  5. Check for a visible dip or soft spot along the route that might indicate a crushed or misaligned section.
  6. Consider adding a cleanout access point if the system doesn't have one, to make future maintenance easier.
  7. Have a drainage contractor excavate and repair or replace failed sections if basic clearing doesn't restore flow.

Tools and parts

  • Garden hose
  • Shovel
  • Plumbing snake
French drain pipeSearch: “perforated drain pipe”

When to call a pro

Call a drainage contractor to excavate, clear, or rebuild a failed French drain system.

Safety

Generally low risk

Generally low risk for a careful person. Stop if anything looks different from what this guide describes.

Related guides

Operator provides AI-generated troubleshooting information. It can be wrong. For safety-critical, electrical, gas, structural, medical, automotive safety, or other high-risk problems, consult a qualified professional.