Unclogging a washing machine drain depends on where the clog is in the line. If your drain is backing up water where the drain hose fits into the house drain line, call a plumber. The clog is within the main drain pipe under the home and requires a professional. If there is no water coming out of the washing machine drain hose, you have a clog either in the drain pump or the drain hose.
Unplug the washing machine power cord from the wall outlet. Turn off the water spigots at the wall.
Open the washer lid and remove the clothes in the tub. Place the large bucket nearby, and start bailing the water out of the tub with the smaller bucket. Pour the water into the large bucket and empty that bucket as necessary. If you have access to a wet vacuum, use it to remove the water from the tub. Empty the wet vacuum as necessary until all the water is out of the tub.
Pull the washing machine away from the wall. You need enough room to work behind the washer, but do not stretch the water supply hoses that connect from the wall to the washer.
Look for the access to the water pump on your washing machine. Some will be clearly visible from the back of the washer. Others may be behind a toe panel at the front of the washer. If your washer has a toe panel, insert a putty knife in the seam between the top of the toe panel and the bottom of the front panel. Feel for the retaining clip three inches from either corner with the putty knife blade. Slide the putty knife blade over the retaining clip and pull the toe panel away from the washing machine.
Place a shallow pan under the water pump where the two hoses connect to the pump. One hose connects to the washer tub and the other to the drain hose. Grab the ends of the spring clamps that secure the hoses to the pump with a pair of pliers. Squeeze the ends together and slide the clamp down each hose. Pull the hoses away from the water pump. Water will spill because there is water in the hoses as well as the pump. Have towels nearby to soak up any spills, and point the end of the hoses over the shallow pan.
Look inside the ports of the water pump for small pieces of clothing such as socks. Sometimes small articles will get in between the inner and outer tub, and find their way into the water pump, causing a clog. Remove any article of clothing from the water pump and install the two hoses to the pump. Secure the hoses to the pump with the spring clamps. Press the toe panel back over the front of the washer.
If the water pump had no clogs, next locate the spring clamp securing the washer drain hose to the back of the washer. Squeeze the ends of the spring clamp together with the pliers and pull the drain hose away from the washer. Disconnect the other end of the drain hose from the house drain pipe. Most drain hoses just bend over into the pipe and may have a clip that will lift straight off the pipe.
Take the drain hose outside and place the end of a garden hose, without a spray attachment, in one end of the drain hose. Turn on the water spigot and push the garden hose through the drain hose until it comes out of the other end. Often a buildup of soap and dirt is clogging the drain hose. Turn off the spigot and pull the garden hose out of the drain hose.
Install the drain hose back into the end of the house drain line and the back of the washer. Secure the hose to the washer with the spring clamp. Push the washer back toward the rear wall. Turn on the wall water spigots, and plug the power cord into the wall outlet. Set the wash cycle to the smallest load setting with hot water. Allow the washer to run through this cycle. The hot water will remove any residual material from the washer drain line.