When you’re planning major bathroom renovations, plumbing diagram bathrooms, showing your existing plumbing lines and your planned changes. The other use of the plumbing diagram bathrooms is to help you gather the building materials.
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