Why does my washing machine drain slowly?

Slow washing machine drainage is usually caused by a clog in the drain hose, the standpipe, or the laundry drain line. Lint, small items, and soap residue build up over time. Disconnect the drain hose and check for clogs. Clean the lint filter if your machine has one. If the standpipe itself is clogged, use a drain snake. If multiple fixtures near the laundry drain slowly, you may have a main drain line issue requiring a plumber.