If this sounds familiar, you'll be happy to know that replacing a disposer is really fairly simple. With today's plastic waste kits, leaks are seldom a problem and the electrical connections are similarly quick and easy. Finally, retail outlets sell good disposers for every household budget. Before you buy, though, it pays to check out your old unit to make sure it's not simply jammed.
The good news is that a leaking gasket can be easily replaced. Most home improvement or local hardware stores will carry them, and they are usually inexpensive. However, depending on the particular model of your garbage disposal, it may require a specially fitted rubber gasket. To ensure that you get the right gasket the first time, write down your garbage disposal’s model number, take it to the store, and ask an employee to match it up for you.
The metal sink flange that sits directly inside the sink drain is typically sealed around the top with plumber’s putty (a clay-like sealant) and then secured from under the sink with bolts. If the plumber’s putty deteriorates, or the bolts loosen, the flange can no longer form a watertight seal between the sink drain and the disposal—which could cause a leak at the top of the unit.
Another common cause for a leaking garbage disposal is the disposal flange. A leak at the very most upper area of the garbage disposal could be the garbage disposal flange which goes through the sink. A garbage disposal flange should be sealed with Plumber’s putty and then tightened from underneath the sink. If this is not tight enough or if it has managed to come loose (which can happen) then the garbage disposal will have to be taken down so the flange can be resealed and then the garbage disposal can be rehung.