What a 200 ft French drain takes
| Item | Amount |
|---|---|
| Drain rock (clean washed stone, 3/4 to 1½ in) | 11.51 cubic yards, 16.1 tons |
| Perforated pipe, 4 in | 200 ft (20 pieces of 10 ft) |
| Non-woven filter fabric | 1,000 sq ft |
| Soil to dig out | 11.1 cubic yards |
For a trench 12 in wide and 18 in deep, with 10% extra stone for uneven trench walls and settling. The stone is the trench volume less the space the pipe takes up, at 1.4 tons per cubic yard.
200 ft of drain, by trench size
Width × depth of the trench, with a 4 in pipe and 10% extra stone.
| Trench | Drain rock, cubic yards | Tons | Fabric, sq ft | Soil dug out, cubic yards |
|---|---|---|---|---|
| 8 × 12 in | 4.72 | 6.6 | 733 | 4.9 |
| 12 × 12 in | 7.44 | 10.4 | 800 | 7.4 |
| 12 × 18 in | 11.51 | 16.1 | 1,000 | 11.1 |
| 12 × 24 in | 15.59 | 21.8 | 1,200 | 14.8 |
| 18 × 24 in | 23.73 | 33.2 | 1,300 | 22.2 |
Fall and outlets on a 200 foot drain
At 1 inch of fall for every 8 feet, a 200 ft drain drops 25 inches, just over 2 feet, from one end to the other. On a lot without that much natural slope the outlet end becomes a deep trench, so one option is to split a long drain into two runs that each fall to their own outlet.
Two runs of 100 ft take the same stone as one of 200 ft: 11.5 cubic yards (16.1 tons) in a 12 by 18 in trench, with 200 ft of pipe and 1,000 sq ft of fabric. Work out the route and the outlets first, then order.
Use clean, washed stone with no fines, wrap the stone (not the pipe) in the fabric, and make sure the drain has an outlet. The fittings, tools and steps are in the French drain materials list, and the method behind the stone figure is in how much gravel for a French drain.
Want to change anything else? The calculator above is the full French Drain Calculator: edit any number and the results update instantly.
Tools & materials for this project
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Frequently asked questions
How much gravel do I need for a 200 foot French drain?
About 11.5 cubic yards, or 16.1 tons, of clean drain rock for a trench 12 in wide and 18 in deep with a 4 in pipe, including 10% extra. A 12 by 24 in trench takes 15.6 cubic yards.
How much fall does a 200 ft French drain need?
At 1 inch for every 8 feet, 25 inches over 200 ft.
How many tons of rock for a 200 ft French drain?
About 16.1 tons (11.5 cubic yards) for a trench 12 in wide and 18 in deep with a 4 in pipe.
Related sizes and guides
Estimates only. Results assume standard materials and simple shapes. Supplier products vary, and the final call on quantity, structure and safety is yours. Check your local code and your supplier's guidance before ordering.