French Drain Calculator
Calculate french drain materials including gravel, pipe, and fabric.
French Drain Materials
Trench Volume75.0 cu ft
Gravel (67% fill)1.86 cu yd (2.61 tons)
Perforated Pipe50 ft
Filter Fabric200 sq ft
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Frequently Asked Questions
How deep should a french drain be?
French drains are typically 18-24 inches deep. The trench must be below the problem water level and slope 1% toward the outlet.
What size gravel for french drain?
1-1.5 inch washed gravel (clear crush) is ideal. Pea gravel is too small and can clog. Never use dirty gravel with fines.
Does a french drain need a pipe?
Yes, a perforated 4-inch PVC pipe wrapped in filter fabric is standard. The pipe collects and channels water to the outlet.