Replacing a garbage disposal

I need to replace our gd. I looks like a simple procedure of dropping the old one out and putting the new one in. Anything I should know before I do it?

I replaced one. It wasn’t too hard. If you replace it with one that’s the same brand, you might be able to use the existing mounting bracket, rather than having to install a new ring / bracket.

Don’t skimp on the plumbers putty.

Assuming the outlet is at the same place vertically from they flange as the old one, and it of the same diameter it is a piece of cake.
Murphy will see to it that both of these conditions will not exist. :rolleyes:

You may have to replace the trap and associated pieces. In fact thinking about it, putting in all new under sink pieces would be a great idea even if not necessary. Think about it. If your trap is metal and old, it is probably corroded somewhat inside. Replacing it will extend the time before it starts to create problems.

Second on the don’t skip on the plumber’s putty.

If it’s hard-wired, consider putting an outlet in, so that when you have to work on it, you can just pull the plug and know for sure that it won’t turn on. I think most brands use a universal bracket, but check on that before you buy, if you are happy with the way it is now, buy a disposal that will work with the existing one, and then you won’t have to worry about the plumber’s putty. Also, it can be difficult to hold the disposal up while trying to thread it onto the bracket, so get someone to help, or figure out how to prop it up under the sink. And if you do replace the drain/bracket, you want the plumber’s putty to ooze out, in a fairly uniform ring-proof of a good seal.

Check your local codes to see if this is allowed.

I must disagree with the “don’t skimp on the plumber’s putty” remarks.

Too much can be as bad as not enough. When you glob on a huge amount of plumbers putty, and let the tightening of the joint squeeze out the excess, it is fairlyl likely that you will actually create or cause weak spots or bubbles in the putty.

For this type of intallation, roll out a 1/4 inch thick “snake” of putty, long enough to wrap three times around the flange seat. More than that and you risk cavitation (as per above) less than that and yoy you will probably be “skimping”…


The only relevant code is the National Electric Code, which tells you to use everything electrical in a manner consistent with it’s listing and labeling. That refers to the folks at UL. If they list and label a model X garbage disposal for “cord and plug” connection, then you’re good. Otherwise, it must be hardwired. Likewise, if a disposal is furnished with a cord cap, unless the instructions specifically state they you can remove that flexible cord and hardwire the appliance, and you do so anyway, you’ve not installed it in accord with the UL listing.

FWIW, every garbage disposal I’ve purchased in the last 8 years (that’d be four garbage disposals) came with a cord with a connector. Well… the cords were always sold separately, but they always had connectors for plugs molded onto the cable.

If you buy a heavy duty gd w/ lots of insulation, it will be heavy and hard to lift up into the rubber collar that holds it against the basket/drain.

I find that using a car scissor-jack to lift the gd up into the collar makes the job much easier. You can gently raise the gd into the collar to just the right height and then tighten the clamp that holds it in place.

I’ve heard that some plumbers use a special device for the same purpose.

Also, I should mention that you’d want a GFI outlet, if you do put one in.

And, wheather it’s hard wired or plugged in, it should have a drip loop (or whatever you call it. Basically, the wiring, at some point before the first junction, should go down and back up (as opposed to being taut), this makes sure that any water that drips on the wiring can drip back into the box or outlet.

And putty, use plenty of putty. If you skimp on the putty you’ll be tearing the whole thing out and starting over when it starts leaking.

Another tip. (For new installs and people that have had it installed for years). If you notice that when you turn it on the collar spins a little. That’s sign that the seal is failing, and you should pull it out and re-putty it.

Ahem. I’ve replaced two InSinkErators in two different houses in the last couple of years. They come with a gasket, and specifically state you should not use putty.