We've got one of those water heaters that sound like a miniature percussion contest is occurring within it's metallic confines...loud snaps, deep gurgles that sound like Grandpa using Listerine, and pings similar to pebbles thrown against a metal door...it's darn noisy. So this weekend we got to flushing out our water heater to quiet the noisy beast down...Think of flushing out your water heater as having the same benefits as a healthy high fiber diet for our own bodies; the flushing action will remove sediment build-up that causes corrosion, reduces efficiency, shortens the life of your unit and also is responsible for those annoying sounds. It's quite a simple procedure, but some careful details need to be noted if you haven't done this before (because you're dealing with super hot water):
First, set your pilot light valve down to the "pilot" setting; do not turn off the gas to the heater.
Turn off the water supply, both hot and cold.
Attach a garden hose to the drainage valve at the bottom of your tank; ours was a plastic valve, which needs to be handled carefully.
Position the other end of the hose safely away outside to drain; we placed our hose into our backyard garden.
Turn on a hot water faucet in the house from a nearby source to allow air into the top of your tank.
Turn on drain valve and allow tank to empty for five minutes.
When tank has completely empried, turn on the cold water supply on to flush out any remaining sediment from the tank.
After 5 minutes, inspect water being evacuated and look for any sediment; if clear, you've properly flushed your tank of accumulated matter and can disconnect hose.
Return the pilot control to the previous setting and allow ample time for the water to heat back up. Turn on hot water supply. Enjoy a quiet and clean water supply.