How do you maintain a French drain?
Updated August 2026
A French drain needs one hose flush a year and a clear, open outlet, because the whole job it does, carrying groundwater away from the foundation, quietly reverses the day silt or roots plug the perforated pipe. Run a hose down the pipe until it flows clean, keep the outlet and any catch basins free of leaves and sediment, and confirm water actually moves after heavy rain. Skip it and a clogged drain pushes water back against the foundation, and re-digging a failed system runs $2,000 to $6,000 against a five-minute yearly flush.
| Task | Interval | Effort |
|---|---|---|
| Flush the perforated pipe with a hose until it runs clear | Yearly | 30 min · DIY |
| Clear leaves, silt, and mulch from the outlet | Yearly | 15 min · DIY |
| Check that catch basins and grates drain freely | Yearly | 15 min · DIY |
| Task | Interval | Effort |
|---|---|---|
| Confirm water is running out the outlet, not pooling | After storms | 10 min · DIY |
| Watch for wet spots or backup near the foundation | After storms | 10 min · DIY |
| Task | Interval | Effort |
|---|---|---|
| Camera-scope the line to find silt or root intrusion | As needed | $150–350 pro |
| Have roots cut and the pipe jetted clean | As needed | $200–500 pro |
What neglect costs
A French drain fails silently. Silt and fine soil work through the fabric, roots find the perforations, and the pipe slowly packs solid, so instead of carrying water off it holds water right where you least want it, along the foundation. That is a wet basement, efflorescence on the walls, and eventually hydrostatic pressure on the foundation itself, whose repairs dwarf everything here. A yearly flush costs an hour; excavating and rebuilding a buried, clogged drain runs $2,000 to $6,000, and foundation waterproofing on top of that is far more.
Leave these to a pro
When a flush no longer clears the line, a pro with a sewer camera can tell you whether it is silt, a crushed section, or roots, for about $150 to $350, then jet it clean or cut roots for another $200 to $500. Full excavation and replacement, if the pipe is collapsed or the gravel is fouled, lands in the $2,000 to $6,000 range. Everything preventive here, the yearly hose flush, outlet clearing, and catch-basin check, is DIY and is exactly what keeps you out of that camera call.
This whole checklist ships as reminders in OnOtto: every task above, on the right schedule for your home, snooze-proof.
Load this checklist as remindersFrequently asked questions
How do I know if my French drain is clogged?
The clearest sign is water where the drain is supposed to have removed it: a soggy yard along the drain line, water pooling at the surface after rain, or a damp basement that used to stay dry. Run a hose into the inlet and watch the outlet; if little or nothing comes out, or water backs up at the top, the pipe is blocked. Slow drainage, a musty smell, and silt at the outlet all point the same way. Confirm with a camera before you dig.
Can I flush a French drain myself?
Yes, the yearly flush is a garden-hose job. Find the cleanout or the inlet, run water in at full pressure, and check that it flows freely and clean out the far end. If flow is weak, a drain-cleaning attachment or a rented sewer jetter pushes silt through. Clear the outlet of leaves and sediment first so water has somewhere to go. If you cannot get the line to run clear by hand, that is your cue to call for a camera and a professional jetting.
What causes a French drain to clog?
Three things, mostly. Silt and fine soil migrate through worn or missing filter fabric and settle in the pipe over years. Tree and shrub roots sense the water and grow in through the perforations, then trap more debris. And in some regions iron ochre, a rusty orange sludge from iron-rich groundwater and bacteria, gums up the pipe fast. Keeping the outlet clear and flushing yearly slows all three, and a fabric-wrapped pipe set in clean gravel clogs far more slowly than a bare one.
How long does a French drain last?
A well-built one, meaning a perforated pipe wrapped in filter fabric and bedded in clean gravel, commonly lasts 30 to 40 years, while a cheap install without fabric can silt up in under a decade. Maintenance is the real variable: a drain flushed yearly with a clear outlet lasts decades, and one that is never touched can effectively fail in a few years even if the pipe is intact. The yearly flush is what separates the two outcomes.