Aggregate & Component Selection
French Drain Materials & Aggregate Guide
The right stone, fabric and pipe decide whether a French drain lasts 30 years or clogs in three. Here is what professionals specify, and what to refuse at the quarry.
Drainage aggregate
| Material | Spec | Verdict | Why |
|---|---|---|---|
| Washed #57 crushed stone | 3/4"–1" angular, ~40% voids, 1.40 t/yd³ | Use | Interlocks, stays put, and stores and moves water fast. The industry standard. |
| Pea gravel | 3/8" rounded | Avoid | Rolls and migrates, lower void space, unstable under turf. Not for drain envelopes. |
| Quarry process / crusher run | Crushed stone with fines | Avoid | Concrete-like fines compact solid and clog fabric and pipe perforations. |
Geotextile fabric
| Material | Spec | Verdict | Why |
|---|---|---|---|
| 4 oz non-woven needle-punched | 90–120 GPM/sq ft flow | Use | Filters silt while passing water freely. Wrap with 12" top overlap. |
| Woven weed barrier | Slit-film, low flow | Avoid | Blinds with fine silt within a few seasons, causing drain failure. |
Drain pipe
| Material | Spec | Verdict | Why |
|---|---|---|---|
| SDR 35 PVC perforated | 4.215" OD, smooth interior | Use | Best flow at low pitch, crush-resistant, and can be jetted clean. |
| Corrugated single-wall poly | 4.55" OD, ribbed | Use | Budget option for short yard runs. Ribs trap sediment; avoid under driveways. |
Recommended components
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4 oz non-woven geotextile roll
3 ft × 100 ft or 6 ft × 300 ft rolls cover most residential runs with a full burrito wrap.
Check priceNDS pop-up relief emitter
Discreet lawn-level outlet that opens under flow and closes to keep debris and pests out.
Check priceCatch basin (9" or 12")
Surface inlet with grate and sediment trap for low spots and downspout tie-ins.
Check pricePeople Also Ask
Can I use pea gravel for a French drain?
Pea gravel is not recommended. Its smooth round stones roll under load, settle unevenly and pack tighter than angular rock, reducing void space. Washed #57 crushed stone locks together, stays stable under turf and keeps about 40 percent open voids for water storage and flow.
What fabric should be used for a French drain?
Use 4 oz non-woven needle-punched geotextile fabric with a flow rate of roughly 90 to 120 gallons per minute per square foot. It filters silt while passing water. Woven landscape or weed barrier fabric clogs quickly with fines and causes drain failure.
Is PVC or corrugated pipe better for French drains?
Smooth-wall SDR 35 PVC is better for long runs, low slopes and anywhere you need to jet-clean the line. Corrugated single-wall poly is cheaper and flexible for short residential runs, but its ridges trap sediment and it crushes more easily under vehicle loads.