Sewer lines are underground pipes that transport wastewater from homes and businesses to treatment facilities. The term HEMS is a four-letter word meaning 'to join two pieces of fabric together with stitches'. SEAMS is a five-letter word meaning 'a line formed by sewing two pieces of fabric together'. MAINS is a five-letter word meaning 'the main pipe in a system of pipes'. Together, these three words describe the components of a sewer line system.