attach drain line to dishwasher. Attach the Drain Line. thread drain line into hole under sink. Thread the Drain Line. adjust height of legs with wrench. Put the Dishwasher Under the Countertop. place copper ground wire under green round screw. Re-Attach the Wires. attach dishwasher supply line. tighten clamp around hose. Click to see full answer. Correspondingly, where does the water line go on a dishwasher?Slide the dishwasher into its place between base cabinets after you complete the electrical and drain hose connections. Attach the opposite end of the supply hose to the empty valve on the dual outlet/dual shutoff valve. Tighten the compression connector with the wrench and turn on the hot water supply.Subsequently, question is, how many water lines go to a dishwasher? Three Mechanical Connections Connecting a new dishwasher requires three connections: a power-cord connection, a water supply connection, and a drain line connection. Also Know, do you need a plumber to install a dishwasher? While it’s not always necessary, in many cases it’s sensible to call a plumber or have the retailer arrange installation. Dishwashers are normally installed close to sinks to reduce the amount of plumbing required, however this isn’t always the case.Does a dishwasher need its own water supply?Though traditionally dishwashers get hooked up to the hot-water supply, you can save even more energy by connecting to the cold water because the heating element in the dishwasher uses less power than a water heater. However, check manufacturers’ literature—some companies’ models must be supplied with hot water.