How to Add a Hot Water Line for a Washing Machine

Determine the routing for the washing machine's hot water pipe to be installed. Check for clearance and routing issues behind the washing machine and under the existing floor. Check for framing blocks, electrical wires, HVAC ducting and plumbing drainpipes that may interfere with the hot water pipe's routing.

Locate the hot water supply pipe closest to the area of the washing machine. Follow the existing water supply pipe route from another fixture, such as a nearby sink, bathtub or water heater.

Close the water heater's cold water supply valve. Open the lowest hot water fixture in the house to drain the hot water supply system. Shut off the washing machine's cold water valve, if so equipped. Remove the washing machine's cold water supply hose with a pair of pliers.

Pull the washing machine out slightly from the wall to access the power supply and drain hose. Pull the drain hose from the plumbing drainpipe and disconnect the washing machine's power cord from the outlet. Pull the washing machine out completely from the wall to gain full access to the washing machine's plumbing.

Measure the area where the hot water supply pipe will be installed and mark the floor with a pencil. Measure 36 inches from the floor for the height of the hot water supply valve. This will hide the valve behind the washing machine while allowing adequate access to the valve in case of emergencies.

Cut a piece of 1/2-inch CPVC pipe to a length of 48 inches and use CPVC primer and glue to attach a drop-ear ell fitting to one end of the pipe. Swab the inside and outside of the pipe end with purple primer, swab the glue directly over the primer then push the fitting onto the pipe.

Drill a hole through the floor with a 5/8-inch drill bit and power drill; the hole should be directly under the desired location for the hot water valve and set at least 1/4-inch out from the wall. Slide the open end of the pipe down through the hole while holding the pipe in your hand.

Mount the drop-ear ell to the wall by driving a screw through the mounting holes on either side of the fitting. Hold a torpedo level on the side of the pipe to ensure it is level before mounting it in place.

Wrap the threads of a boiler drain valve with Teflon tape, screw the valve into the drop-ear ell fitting and tighten it with an adjustable wrench. Teflon tape should be wrapped clockwise with the threads so it doesn't back off the threads when screwing it into the drop-ear ell fitting. Turn the boiler drain valve clockwise, if necessary, to ensure the valve is closed.

Route the open end of the 1/2-inch pipe up to the closest existing hot water supply pipe. Use various 90- and 45-degree elbow fittings to route the piping around any obstacles.

Cut the existing hot water supply pipe with a pair of CPVC cutters to provide a point to tie in the washing machine hot water line. This requires two separate cuts spaced 1/2-inch apart to allow room for a tee fitting.

Apply primer and glue to the three ends of the 1/2-inch tee fitting and to all three ends of pipe. Push the pipes firmly into the fitting to connect the hot water line and wait for the glue to dry for at least 45 minutes before continuing.

Turn on the hot water heater supply valve and wait for the water heater to fill.

Reconnect the cold water supply hose between the washing machine and the cold water supply line. Use an additional supply hose to connect the new hot water line to the hot water feed on the washing machine. Plug the washing machine back into the power outlet.

Turn on the washing machine, adjust the controls for a hot water wash and check that the supply lines and boiler valves are not leaking. Push the washing machine back into place against the wall.