Sink Drain Pipe Size Code

Below our tables 1 and 2 summarize common plumbing code specifications for fixture venting and vent pipe sizes and distances that a plumbing fixture can be located horizontally from the vent stack.

Sink drain pipe size code.

Horizontal drain pipes connecting the sink drains to the trap must have a minimum slope of 1 4 inch per foot toward the trap. The last size is 4 inch drain pipe that can be connected to 160 units in horizontal stack and 240 units in vertical stack. Bathroom vanity with cooper sink. To be safe install more supports than are required.

All the pipes that connect to the tailpiece including the p trap assembly. Tables of plumbing drain pipe vent pipe sizes critical distances to plumbing fixtures. A single trap can service more than one sink but adjacent drains cannot be farther apart than 30 inches. 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.

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. Compare the fixture to the minimum sizes of drainage pipe by fixture table. You ll see these distances also in our sketch at left. This pipe size is commonly used for sanitary drainage.