underground
gas, sewage, waste, water
the hot and cold water pipes

drain (usually drainpipe), drainage, exhaust, heating, outlet, overflow, plumbing (esp. AmE), service (BrE), supply
broken, burst, cracked, frozen, leaking, leaky
blocked (esp. BrE), clogged (AmE)
concrete, copper, iron, lead, metal, plastic, PVC, steel

length
to join two lengths of pipe together
Copper pipe is sold in lengths.

install, lay, run
He laid the pipes under the floorboards.

connect
insulate, lag (BrE)
Insulating your pipes will save on your heating bills.

lead, pass through sth, run
The pipes lead into the river.
The pipes will have to pass through the wall.

burst, freeze, leak

through a/the pipe
pipe for
the pipe for the hot water

pipe from, pipe to
The pipe from the boiler to the bathtub.

clay
peace
crack, opium, etc.

smoke
light
fill
draw on, puff away at, puff away on, puff on

smoker
smoke
tobacco
cleaner

the bowl of a pipe, the stem of a pipe