A garbage disposal is a wonderful appliance. Rather than having to deal with disgusting food refuse stinking up your kitchen garbage can, you simply wash the excess scraps down the sink, turn on the disposal, and let the grinding blades take care of everything. And if you’ve ever lived anywhere without one, you know how convenient they can be.

Unfortunately, sometimes, these units can fail or need to be replaced. The good news is that installing garbage disposal on your own is fairly easy and doesn’t necessarily require a professional. Learn how to install your own garbage disposal through our step-by-step process.

Supplies Needed

  • Screwdriver
  • Hammer
  • PVC cutter
  • Wire nuts
  • Plumber’s putty
  • Garbage disposal

Installing a Garbage Disposal

1. Your first step in installing a garbage disposal is to remove your existing assembly. However, you definitely want to place a large pan or shallow bucket below your kitchen sink in order to catch any water that could spill out from the drain as you disconnect it. Keep a towel nearby too. Now, begin by removing your existing assembly including the drain basket and P-trap.

2. Open up the box that houses your new garbage disposal. If the flange is pre-assembled, use your screwdriver to gently remove the ring and loosen the fasteners.

3. You will now apply putty to the flange gasket. Locate your flange gasket, if it came with a rubber gasket, remove this. Plumber’s putty is your best option and will give your seal a longer life than the rubber gasket. Roll the plumber’s putty into a snake shape about 3/8-inch in diameter. Make sure it’s long enough to wrap around the gasket, under the flange. Now, gently press the putty evenly around the underside of the flange, just like you would a pie crust.

4. Before attaching your new gasket, clean and wipe out your kitchen sink. Make sure there’s no moisture and that any gunk around the drain opening has been thoroughly removed.

5. Now, take your flange and insert it onto the top side of your sink. Attach the fastening system on the underside of your sink. Apply pressure to the flange from above. You may want another set of hands to help with this. Alternatively, you can use a heavy object to help keep the flange in place so you can attach the fastening system on the underside of the sink. You should be able to see the plumber’s putty oozing out from under the edge of the flange all around. If you don’t see this, you haven’t put enough putty on the flange. Remove and start over if you need to. If you do see putty all around the flange, carefully trim the excess with a rag, but only after a complete seal has been formed.

6. You can now attach the mounting plate to the underside of the sink. Use your screwdriver to fasten the screws, but don’t over-tighten. If you’re worried, start by attaching them first with just your hands, and then only use the screwdriver at the very end to guarantee a good seal.

7. Grab the tailpipe and attach it to the rubber seal on the side of your new disposer unit. You will secure it with the metal spring ring or the metal bracket that is attached to the tailpipe.

8. To attach your disposer unit to your flange, align the two together from the underside of your sink. Press the disposer into place against the flange and secure it loosely by rotating the lower mounting ring onto the ramp tabs of the upper mounting ring. Continue rotating the unit until the entire drain assembly is aligned. You may need to use a sturdy object to prop your disposer unit up as you rotate and align everything.

9. It’s now time to connect the P-trap. Using your PVC cutter, trim the extender pipe and then connect your disposer to your P-trap. With the drain assembled, rotate the lower mounting ring until all three mounting tabs are locked over the ridges that are in the slide-up ramps. You can now tighten these with a screwdriver.

10. Your unit is now installed, but you’ll want to make sure it’s secure before you start using it. Take the drain stopper and place in the drain, then fill the sink up with about an inch of water. Check under the sink for any leaks. If there are leaks, there’s an issue with your plumber’s putty seal. If you don’t detect any leaks, remove the stopper and allow the water to fill up the drain and P-trap. Continue checking for leaks and tighten any spots and needed.

Your garbage disposal is now ready for use! Plug it into a GFCI-protected receptacle. Move and organize your cords as needed so they don’t get caught in a mess under your sink.

Optional Step

If your dishwasher needs to drain through your disposer, there is another step necessary for you to follow in your garbage disposal installation — you will need to locate the breakout plate inside the inlet port. Gently remove it by tapping it with a hammer. You do not need to do this if your dishwasher won’t be draining into your unit.

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