Design Notes:

56" to bottom of inlet gasket
54" to bottom of outlet gasket
Top and bottom matching key joint, sealed
Tanks are steel rebar reenforced
Manhole access to each compartment
4" PVC coupling cast in for inlet and outlet

Capacity: first compartment 500 gallon
Second compartment 1,000 gallon

Do not bury in traffic areas

Excavation Dimension
Width 7.5"; Length 12.5';
Depth preferable to have 6" to 12" of cover over the top of the tank.

Options:
Larger inlet and outlet
Size and location of vent
Cast iron ring and cover