French Drain Calculator
Plan your French drain project by calculating materials and requirements
Our French drain calculator helps you determine the materials needed for your drainage project. Follow these steps:
- Enter your drain length in inches
- Specify the drain width (standard is 18 inches)
- Input the drain depth (standard is 24 inches)
- Enter prices for gravel, pipe, and landscape fabric
The calculator will provide estimates for trench volume, materials needed, and total cost.
A French drain is a drainage system that includes:
- Gravel-filled trench for water collection
- Perforated pipe for water transport
- Landscape fabric to prevent soil infiltration
- Proper slope for water flow
- Connection to drainage outlet
- Optional surface grates or catch basins
French drains help prevent water damage by redirecting surface water and groundwater away from structures.
Essential materials and tools for French drain installation:
- Drainage gravel (3/4 inch or larger)
- Perforated pipe (4-inch diameter typical)
- Non-woven landscape fabric
- Shovel or trenching tool
- Level and string line
- Tape measure
- Wheelbarrow
- Safety equipment
- Call utility companies before digging
- Ensure proper slope (minimum 1% grade)
- Install fabric before adding gravel
- Place pipe with holes facing down
- Use clean gravel without fines
- Overlap fabric edges properly
- Plan for proper water discharge
- Consider local building codes
How deep should a French drain be?
Standard depth is 24 inches, but can vary based on your needs. The drain should be deep enough to intercept water flow and protect foundations, typically 2-3 feet deep.
What type of gravel is best?
Use clean, washed gravel that's 3/4 inch to 1-1/2 inches in size. Avoid rounded stones as they don't lock together as well as angular gravel.
Do I need a permit?
Check local regulations as permit requirements vary. Some areas require permits for drainage work, especially if it affects neighboring properties.