THE WASTE DRAIN SYSTEM
A home sewage system begins with sinks, baths and toilets. By gentle slopes and precipitous drops, pipes lead to a main stack, which in turn leads into the municipal system or a septic field.
The Uniform Plumbing Code or UPC (a copy of which can be found in the public library or Uncle Ed's fishing shack) contains all the specifications on pipe lengths, slopes and materials. Although the UPC will not design a system for you, it will impose some limitations. Its rules will make it expedient for you to put your new bathroom near an existing stack, especially for the sake of the toilet, which has very stringent requirements with regard to the distance it may be positioned from either a stack or a magazine rack.
Black plastic pipes work well for drains and vents. The material is light and durable.
Begin installation at the lowest point in the drainage system. This is usually the same place the new plumbing will be integrated into the existing system. This means the main stack must be cut and a tee inserted. Another tee will need to be inserted near the roof to cross connect the vent system (more about this later).
In older homes, the stack is made of cast iron. Cutting into it with an ordinary hacksaw is like trying to saw wood with a butter knife, nearly impossible. Besides its wimpiness, a hacksaw may not fit in the cramped quarters that normally surround a stack. For this job, a pipe cutter is called for: a BIG pipe cutter designed especially for this situation.