A funky smell from your water dispenser, discolored ice cubes or reduced water flow might mean the water lines in your refrigerator need cleaning, and the procedure for flushing them isn't complicated. Before you go to the trouble, though, change the water filter; if it's near the end of its life, it may not be doing its job.
During the cleaning process, you'll probably want to take the water reservoir out of the unit so you can clean and disinfect it. If flushing doesn't solve the problem, you may need to replace some of the lines or the reservoir itself.
The Water Delivery System
Most refrigerator models have a similar water system that consists of distribution valves for the water dispenser and ice maker, a water reservoir and tubes to connect these parts. You'll see the tubes running on the outside of the back panel, but you may have to remove part of that panel to access some of the connections. The reservoir is usually accessible inside the refrigerator compartment. The water supply tube coming from your house plumbing connects to the main distribution valve by means of a compression fitting.
Flushing the System
The flushing procedure should start with the main supply tube. Once that's clean, flush the tubes that feed the reservoir and clean the reservoir.
Flush the Main Supply
Unplug the refrigerator and turn off the water valve. It's usually in an outlet box in the wall behind the refrigerator; if not, turn off the main shutoff downstairs in the basement. Pull the refrigerator forward away from the wall.
Disconnect the from the refrigerator, using a wrench. the supply tube is the one that connects to the water valve in the house plumbing. Point the free end of the tube -- the one you just disconnected -- into a bucket and turn on the water valve. Let the water run for about 10 seconds, then turn the valve off.
Hook the supply tube back up to the refrigerator and tighten the connector with the wrench.
Clean the Reservoir
The reservoir is usually located in the refrigerator compartment, behind the crisper. If you don't see it there, consult your owner's manual for its location.
Disconnect the tubes from the reservoir. Unscrew the reservoir and remove it from the refrigerator.
Empty the water out of the reservoir and clean it with a solution of 1 cup of vinegar per gallon of water. You can also clean it with bleach -- 1/2 cup per gallon -- if you don't mind the bleach odor.
Fill the reservoir with clear water and replace it. Reconnect the tubes by pushing each connection together until it locks.
Flush the Feeder Tubes and Prime the System
Disconnect one of the outlet tubes from the distribution valve on the back of the refrigerator, using a wrench. Locate the connector on the other end of the tube, which is usually near the top of the refrigerator, and disconnect it. Take this tube to the sink, squirt a couple drops of dish soap into it and run warm tap water through it until the suds stop and the water runs clear. Replace the tube. If the refrigerator has two tubes, clean the other tube in the same way.
Turn on the main water valve to pressurize the water system.
Activate the water dispenser. Keep the lever down until water streams out in a continuous flow. There isn't an easy way to clear the ice dispenser. The best way to do it is to discard all the existing ice cubes and keep discarding any that show signs of contamination. Eventually, the contamination should disappear.