What Is the Standpipe on a Washing Machine

A laundry standpipe connects a washing machine’s drain hose to a home’s waste stack. While it might be tempting to simply connect your washer to any other convenient drain line, doing so increases the risk of water overflow and sewer fumes.

Why do you need a standpipe for washing machine?

The standpipe assembly keeps the water level of the washer tub below that of the drain, preventing siphoning from the drain or sewer line back into the washer. When backflow does occur, siphoning can cause water to flow back into the washing machine from the drain, or out of the drain onto the floor.

What's a standpipe on washing machine?

This type of washing machine trap is the traditional washing machine standpipe trap. It is used when a washing machine has a waste pipe connection that is separate from the kitchen sink, i.e. when a washing machine is sited in a utility room.