Family Handyman DIY Tip of the Day: Inexpensive Wet Basement Solution. Sloping the soil away from the house will take care of the problem most of the time. Firmly pack clay soil around the foundation, with at least a slope over the first 4 ft.
Soil stack is for human waste, anything else is carried by a waste stack. Vents are attached to these stacks. Above the highest stack is vent stack the vents all the bad gases from all the stacks thru the roof out into the air