What Are the Two Pipes Behind a Washing Machine?

Water In

• The water in grandmother’s wash tub came from a hose or buckets carried by grandmother. Today’s washing machines use water delivered by the city water supply or a pump from the home’s well. Two pipes, visible behind the washer or concealed within the wall, bring water to the machine. The first brings cold water and the second brings water from the home’s water heater. Metal water supply pipes are customarily no more than 1 inch in diameter. Faucets or lever mechanisms control the flow of water and connect to the machine through hoses.

Water Out

• Waste water left grandmother’s wash tub through a drain in the bottom of the tub, either into a basement drain or onto the backyard. A second pair of pipes that may be visible behind your machine comprise the modern two-piece drain for waste water. Water exits the machine during the spin cycle through a 2-inch plastic or synthetic rubber curved pipe. The end of this pipe dumps into a slightly wider polyvinylchloride (PVC) pipe that rises from the floor. PVC piping is often white.

Built-Ins

• New homes may not have any water pipes or waste pipes visible behind the machine. Both water supply and PVC waste pipe access may be made through a niche built into the wall near the washer. If, however, the machine is moved, say, to another floor, supply and drain pipes must be brought to the new location. In addition, the drain must join an existing drain and vent stack.

Other Considerations

• Consult your owner’s manual to identify other pipes on the back of your washing machine. Some special features, such as a steam cycle, require air pipes or additional water connections. Another pipe behind a stacked laundry washer-dryer combination may not be part of the washing machine at all. The 4-inch dryer exhaust is, optimally, a galvanized length of rigid stovepipe.