Below-Grade Drainage Calculator

Drain tile sizing from water table and soil permeability.

Foundation perimeter (ft)

Foundation depth (ft)

Water table depth (ft)

Soil type (1=gravel, 2=sand, 3=silt, 4=clay)

Trench width (ft)

Design rainfall (in/hr)

Tab to move between fields

Design flow rate (GPM)

8.73

Pipe diameter (inches)4

Drainage gravel (tons)74.1

Gravel volume (cu yd)52.9

Filter fabric (sq ft)2,220

Drainage board (sq ft)960

Estimated material cost ($)$4,769

Soil NameSilt

How to Use This Calculator

Enter Foundation Perimeter (ft) — the total linear feet of foundation wall requiring a drainage system.
Input Foundation Depth (ft) and Water Table Depth (ft) to determine the hydraulic head the system must manage.
Select Soil Type (1=gravel, 2=sand, 3=silt, 4=clay) — clay soils require larger pipe and more gravel than sandy soils.
Enter Trench Width (ft) and Design Rainfall (in/hr) from your local 10-year, 1-hour storm intensity map.
Review Design Flow Rate (GPM) and Recommended Pipe Diameter to specify perforated drain pipe.
Use Drainage Gravel (tons), Filter Fabric (sq ft), and Estimated Material Cost for procurement and bid preparation.

Ad Placeholder

Related Calculators

Material and cost from foundation wall area.

Membrane area and injection quantities for tunnel systems.

Crystalline waterproofing coverage and application rate.

Test procedure from wall type and ASTM standard.

Ad Placeholder