Washing machine drainage systems fail in three specific zones. Troubleshoot them in order from the simplest internal fix to the deepest structural pipe blockage. 1. The Internal Pump Filter
"HE machines are great for the environment, but they struggle to flush heavy soils and thick detergents through long drain lines," explains Mark Rizzo, a veteran appliance technician. "Because they use so little water, the water velocity is lower. If you use too much detergent, it doesn't fully dissolve. It turns into a gray sludge that coats the pipes like cholesterol in an artery."