The warranty period for popular garbage disposal models hardly ever exceeds 10 years, but you should expect a garbage disposal lifespan to be more than that. The consensus among plumbers is that garbage disposals can easily last from 12 to 15 years at a minimum, and they can last even longer with the proper care. You take proper care of your garbage disposal by following the manufacturer's recommendations for your unit, watching what you put into it and periodically cleaning it.
The 12- to 15-year life expectancy of a garbage disposal is an approximation. Some units last longer, particularly if they are sized correctly for the amount of food waste they handle. For example, a family of four that eats meals at home can use their 1/2 HP unit for at least the warranty period, and probably a little longer. But a 3/4 or 1 HP model would last longer simply because it has more grinding power.
The amount of available space under the sink or energy considerations may compel you to purchase a smaller model than you prefer. If so, you should be prepared to replace it sooner than if you were able to install a larger model. If space and energy consumption are not issues, go ahead and install a 1 or 2 HP model, and it may last as long as the sink. Much, of course, depends on how you use the garbage disposal (or, as Canadians say, garburetor) for food disposal.
Which Parts of a Garbage Disposal Wear Out?
Inside a garbage disposal, you'll find three key components that do all the dirty work. Every disposal has them, although their design may vary from model to model.
The flywheel is the moving part of the garbage disposal. It's a horizontal disc that covers the bottom of the canister and is attached to the motor shaft. When you turn on the power, this is the part that spins.
The impellers are loosely attached to the surface of the flywheel and can rotate. They are usually made of metal, and their job is to fling food waste toward the sides of the canister.
The shredder ring is the part of the garbage disposal that does all the mashing. Similar to a cheese grater, it surrounds the flywheel and turns all the food the impellers fling its way into pulp, which slides down through a small gap between itself and the flywheel and into the drain.
The motor and shredder ring are the most vulnerable parts of the entire unit. When the shredder wears out or gets clogged and loses its ability to mash food, the motor has to work longer and harder to process what you put in the disposal. Not only that, but food that's not completely processed food is more likely to get stuck in the gap between the flywheel and shredder ring, which is also bad for the motor and shortens the garbage disposal useful life.
How to Keep the Shredder Ring Sharp
If you've ever grated cheese, you know the process gets more difficult the longer you do it because thick, sticky cheese gets stuck in the grater. The same thing happens to the shredder ring in a food disposal system when you put in greasy foods or starches, such as potatoes, pasta and rice, and they congeal. You can't clean the shredder ring by washing it as you would a cheese grater, but there is an easy way to clean off hardened greases and starches.
Fill the canister with ice cubes from the freezer, then pour in about 1/2 cup of coarse salt to lower the temperature of the ice. Allow the ice and salt to sit in the canister for about an hour to give the supercooled ice time to harden the greases and starches clogging the shredder ring. Turn on the water and the garbage disposal and grind all the ice. The rough edges of the ice will clear all the gunk off the shredder blades and sharpen them at the same time.
Just after doing this, it's a good idea to slice up one or two oranges or lemons and run them through the disposal. You can also add them to the ice as it's sitting in the canister. Orange and lemon peels are great deodorizers and help keep the disposal smelling fresh.
Indications Your Garbage Disposal Lifespan is Reaching its End
Even with proper care, the shredder ring in a garbage disposal will eventually get dull. When this happens, a few telltale signs will alert you to the fact that's it's time to replace the disposal.
You have to clear clogs frequently. When a food disposal clogs, the unit shuts off, and you have to clear the clog and push the reset button. It's normal for this to happen occasionally, but if it happens frequently, it means the shredder ring is dull.
You see leaks under the sink. Some leaks are caused by loose plumbing pipes, but if you tighten all the pipes and you still see water, the garbage disposal itself may be leaking. This is due to worn seals that require disassembly and service. It's usually cheaper to buy a new garbage disposal.
You notice persistent odors that you can't eliminate. Beside running ice and citrus fruit through the unit, you can also get rid of odors with vinegar, baking soda and dish soap. If none of these methods work, odor-causing microorganisms have lodged deep in the mechanism, and it's time to replace the unit.
The motor makes strange noises. When the motor wears out, some of the gears may start slipping, and the garbage disposal may hum, whine or rattle. It' far easier and cheaper to replace the garbage disposal than it is to try yo fix the motor.
How to Get the Most from Your Garbage Disposal
Your garbage disposal will last a lot longer if you refrain from grinding items such as bone, eggshells (the membranes clog the shredder), coffee grounds, fibrous fruit and vegetables (including celery and banana peels), starchy foods like pasta, rice and potatoes, greasy and oily foods, and fruit pits,
You may be wondering, then, what items you can put down your food disposal. Here's a partial list: meat and fish scraps, vegetablesM fruit and fruit rinds, non-starchy grains, such as oats and wheat, and nutmeats.
You may forget from time to time and put a few eggshells or some old rice in the disposal. As long as you don't make it a habit, your disposal will probably handle them without a significant reduction in its service life, especially if you take the time to clean the shredder ring on a regular basis. However, the toll will be greater on a small machine serving a household that actually needs a larger, more powerful model.
Chris Deziel is a contractor, builder and general fix-it pro who has been active in the construction trades for 40 years. He has degrees in science and humanities and years of teaching experience. An avid craftsman and musician, Deziel began writing on home improvement topics in 2010. He worked as an expert consultant with eHow Now and Pro Referral -- a Home Depot site. A DIYer by nature, Deziel regularly shares tips and tricks for a better home and garden at Hunker.com.