Septic Systems

Septic systems handle waste from drain systems in buildings, processing waste through septic tanks and leaching areas. This tool helps determine septic tank capacity, grease interceptor requirements, and leach field sizing based on soil absorption rates.

Septic Tank Volume (gallons)	Maximum Capacity (m³)	Single Family Units (bedrooms)	Multiple Family Units (units)	DFU
750	2.8	1 - 2		15
1000	3.8	3		20
1200	4.5	4	2	25
1500	5.7	5 - 6	3	33
2000	7.6		4	45
2500	9.5		6	60
2750	10.4		7	70
3000	11.3		8	80

Type of Soil	Absorption Capacity (gallons/ft²)	Absorption Capacity (liter/m²)
Clay with small amount of sand or gravel	1 - 1.5	40 - 60
Clay with small amount of sand or gravel	1.5 - 2	60 - 80
Sandy loam/clay	2.5	100
Fine sand	4	160
Coarse sand or gravel	5	200

Calculator

Inputs

24-Hour Wastewater Load (gallons)

Soil Absorption Capacity (gallons/ft²)

Results

Required Leach Field Area-- ft²

Leach Line Guidelines

Maximum length of each line: 100 ft (30 m)
Minimum spacing between lines: 10 ft (3 m)
Minimum depth of leach line: 12 in (0.3 m) or deeper if soil freezes
Elevation rate: Approximately 1%