Some older sinks may have drains that connect to a 1 1 4 inch tailpiece but most modern drains have a 1 1 2 inch outlet.
Sink drain pipe size code.
This pipe size is commonly used for sanitary drainage.
Bathroom vanity with cooper sink.
For instance the minimum pipe diameter for a washing machine drain is pipe with a 1 1 2 inch diameter.
The horizontal pipes connect to the trap with a double wye tee which has two y shaped inlets and one outlet.
Tables of plumbing drain pipe vent pipe sizes critical distances to plumbing fixtures.
This is the minimum size to use for building sewer or drain pipe that is connected to the toilet.
Horizontal drain pipes connecting the sink drains to the trap must have a minimum slope of 1 4 inch per foot toward the trap.
You ll see these distances also in our sketch at left.
According to most codes copper supply pipe must be supported every 6 feet galvanized or black steel pipe every 12 feet pvc or abs drainpipe every 4 feet and cast iron pipe every 5 feet.
To be safe install more supports than are required.
Compare the fixture to the minimum sizes of drainage pipe by fixture table.
A single trap can service more than one sink but adjacent drains cannot be farther apart than 30 inches.