Important Numbers 4

101.6 mm

Minimum extension of bituminous coating below the water line of concrete septic tanks and shall cover all internal area above that point

GA 12 (2.8 mm)

Minimum wall thickness of steel septic tank internally and externally protected from corrosion

25.44 mm

Raking depth to remove loose materials from trenches before placing filter material

19.1 - 63.5 mm (3/4" to 2-1/2")

Sizes of clean stone gravel slag or similar filter material to be placed in trench

1.5 m

Termination of filter material from seepage pit excavation when used with disposal fields

25.4 mm

In distribution box minimum vertical clearance of the invert of inlet above the inverts of outlets

More than 152.4 lineal meters

Length of each line where dosing tank is required

3-4 hours

Intervals of sewage discharge from the dosing tank through automatic siphon or pump

2

Number of siphons or pumps when total pipe length exceeds 304.8 lineal meters

1

Minimum number of drain lines per field

305 m

Maximum length of each line in a disposal field

457.2 mm

Minimum bottom width of trench

914.4 mm

Maximum bottom width of trench

304.8 mm

Minimum depth of earth cover of drain lines

457.2 mm

Recommended depth of earth cover of drain lines

304.8 mm

Minimum thickness of filter material under drain lines

50.8 mm

Minimum thickness of filter material over drain lines

1.2 m

Minimum spacing between leaching beds

1.8 m

Horizontal spacing of distribution drain lines center-to-center

0.9 m

Distance of the perimeter of leaching bed from a distribution line

Less than 2 years

A cesspool without septic tanks may be installed when a public sewer will be available in ___

6.1 m

Minimum sidewall of cesspool below inlet

403.8 mm

Minimum extension of vented leg downward into an existing pit

152.4 mm

Minimum vertical clearance of outlet flow line below inlet when overflow pits are added

2

Minimum number of compartments for interceptors

3 m

Minimum horizontal distance of tree from septic tanks seepage pits or cesspools

4.6 m

Minimum horizontal distance between leaching system and ground surface in sloping ground

304.8 mm

Minimum extension of vented leg fitting below inlet fitting in seepage pit

2.2 m

Minimum diameter of seepage pit

101.6 mm

Minimum thickness of seepage pit concrete wall

304.8 mm

Thickness of concrete block in seepage pits to be chamfered

152.4 mm

Minimum thickness of clean 19.1 mm gravel or rock in excavation voids

17

225 kPa, Minimum compressive strength of brick or block in seepage pit construction

3 m

Minimum sidewall of seepage pit below inlet

50.8 mm

Minimum thickness of cement mortar covering for seepage pit arch or dome

152.4 mm

Minimum extension mortar covering beyond sidewalls of seepage pit

127 mm

Minimum thickness of reinforced concrete slab cover of seepage pit

19.2 kPa

Minimum earth load support capacity of slab cover for seepage pit

228.6 mm

Minimum dimension of inspection hole for seepage pit

457.2 mm to 1.2 m

Depth of top of seepage pit arch or cover below ground surface

203.7 L/m²

Maximum absorption capacity for coarse sand or gravel

162.9 L/m²

Maximum absorption capacity for fine sand

101.9 L/m²

Maximum absorption capacity for sandy loam or sandy clay

44.8 L/m²

Maximum absorption capacity for clay with considerable sand or gravel

33.8 L/m²

Maximum absorption capacity for clay with small amount of sand or gravel