Garbage Disposer Troubleshooting and Repair

411 plumb Troubleshooting and repairing a garbage disposer is actually quite an easy task. In many cases it is as simple as using an Allen Wrench or a tool supplied by the manufacturer inserted into the bottom of the disposer to turn the disposer shaft to unjam the disposal, then pressing a reset button to fix the problem. The key is recognizing where the problem is and fixing it or, recognizing when its just time for a new disposer.

Worn Out Disposers

Frequently a disposer will continue to run long after it has been worn out. Many of the lower priced disposers frequently called “Builder Grade” have a grinding chamber made of galvanized steel. These units have a relatively short life expectancy and all they really are is a cheap disposer that the seller can say is there. The manufacturers typically offer only a one or two year warranty on these product lines. The teeth of the grinding chamber on these “Builder Grade” units rust and wear away quite quickly and once that occurs the waste is pushed into the line without being ground up and the drains tend to clog from this. Look inside your disposer with a flashlight at the grinding teeth around the edge of the turntable to see if the teeth are worn. Take a look at the teeth of the disposer in the picture and compare them to your disposer. Another sign of a worn disposer is water leaking through the unit. Water leaking through the unit is a sign that the shaft seals are worn out. If the disposer is worn out there is no repair option in most cases and replacement is the only option. There are a few manufactures that offer replacement parts but I question whether they are even worth repairing. If your disposer is worn out I would suggest replacement with a new Insinkerator Evolution Series disposer if you are planning on keeping the house for more than a few years.

The Disposer Does Not Run

View of Bottom of Disposer showing circuit breaker reset button and unjamming wrench hole.

View of Bottom of Disposer showing circuit breaker reset button and unjamming wrench hole.

If the Disposer does not run there is no other symptom that matters except being worn out. A disposer that is not running will rapidly clog with food debris giving the appearance of being clogged. Merely rotating the turntable will in many cases instantly start the disposer draining again but without the unit running it will clog again rapidly.  To check the disposer turn the turntable with the unjamming wrench or if the disposer does not have a hole in the base for unjamming insert something into the top of the disposer to catch the grinding hammers on the turntable and turn the turntable to free up the jam until the turntable turns freely again. Press the circuit breaker reset button and turn on the disposer. In most cases it will run again and be ready for use. In some cases something may be banging around inside the grind chamber shut the disposer back off and inspect the grinding chamber to see the object and remove it. If the unit only hums but does not run check for jamming again, if the turntable is free spinning and the motor only hums the disposal requires replacement. If the disposer does nothing recheck the circuit breaker reset button and try turning it on again. If the disposer still does nothing make sure that power is available to the disposer when turned on. If there is power supplied to the disposer and it does nothing then replacement is needed.

The Disposer Runs But Water Doesn’t Drain From the Sink

Garbage Disposer Grind Chamber showing condition of grinding teeth.

Garbage Disposer Grind Chamber showing condition of grinding teeth.

In this case unless the disposer is worn out the problem is only a clogged drain. Sometimes when too much garbage is processed at once or the wrong things are put in a disposer clogs can result. Remove as much water as possible from the sinks before starting to work. Place a container large enough to catch the remaining water in the sink, disposer and pipes under the drainpipes of the sink and take the drainpipes under the sink apart to see if you can find where the plugged section is. Frequently the clog will be in the p-trap, baffle tee where the two sinks of a double sink come together, or in the disposer elbow itself. If you find the clog in the drainpipes under the sink reassemble the pipes and test the drainage. Hopefully this clears the clog and gets you drain running again. If the pipes under the sink are not clogged then the clog is past where it can be reached without a drain snake. If the drain requires snaking I would recommend calling a plumber to snake the line clear with an electric powered snake. With a clogged disposal drain I recommend a close inspection of the disposer grinding chamber to make sure it is working properly and not sending ungrounded food waste down the drain. If the disposer is badly worn the line will re-clog.

If you have any questions or comments please leave them below and I will reply.

Posted in Garbage Disposers, How To Plumbing Tips Tagged with: , , ,
28 comments on “Garbage Disposer Troubleshooting and Repair
  1. Gary Boyajian says:

    I just installed a 3/4 horsepower Insinkerator Evolution Series disposer (nice unit) in the kitchen, and everything works fine – proud to say I got it all in and it worked with no leaks on the first try (and it only required 2 trips to the local Home Depot). I had to re-do the drain pipe coming out of the wall because the elbow was poorly positioned to work with the double sink, so I replaced all the PVC from the wall out, and everything flows well.
    The reason I replaced the original was probably because of what you described above – it was worn out and not grinding waste thoroughly. It would clog at the baffle T under the other sink, below the trap. It would typically happen when the wife put a lot of vegetable waste down the disposer.
    My only problem is, now when the wife runs the disposer, waste water backs up slightly into the other sink. When I put the new lines in, I did not use a baffle T under the other sink because I thought it was contributing to the clogging at that point. I used a T with no baffle in it. Is this the reason for the backup into the other sink?
    Also, the drain line coming out of the disposer runs dead level over to the T under the other sink. I have limited space below the sink, and could not run it any other way. I wondered if this was contributing to the problem, but the straight drain line that comes with the unit appears to be designed for this. The disposer drain line runs horizontally into the T, and directly below the T is where I have the P trap.
    Sure would appreciate your feedback – I have done 3 or 4 disposers over the years, never had this problem.
    Gary Boyajian

    • Redwood says:

      Hi Gary,
      Yes You do need the baffle tee or, it will come up in the other sink just like you describe.
      Most users really do like the Evolution Product Line.

  2. cathy hughes says:

    just installed new garbage dis. after other just stopped. new one wont work either we have juice up to end of wire that goes into disposal and new ends on wires any ideas before my hubby loses his mind thanks so much cathy

    • Redwood says:

      Hi Cathy,
      Without being there to check it out all I can do is offer a guess.
      My guess and the first thing I would check is if there is still voltage at the disposer connection with the disposer connected and ready to run. Sometimes there can be a bad connection in the circuit where a connection is barely made that reads okay until you put it under load. That is where I would start.

  3. Bruce Johnson says:

    Insinkerator 11 years old, suddenly started making loud roar that when you turn it off it finishes with a thump, thump,..thump…..thump……..thump. Spent hours with a flashlight and my hand down in it looking for foreign object but to no avail.

    • Redwood says:

      Hi Bruce,

      If it is a Insinkerator Badger unit then I can tell you that it is long overdue for replacement.
      If it is one of the upper end models it probably is due. A close inspection may show something caught in the disposer.


  4. Peter armfield says:

    I have an Insinkerator Badger disposer going on 7 years old. Works fine except that it now has a leak coming from a small hole that is near the top of the bottom Half of the outer metal housing. This appears to be a small slit 1/8 inch long that was result of an impact abrasion rather than a rust through. Because it is near the upper part of the lower half of the housing it leaks only when disposer is being run. Should I try to repair with an epoxy product or other method or just replace unit? Thanks

    • Redwood says:

      Hi Peter,

      The Insinkerator Badger line is an inexpensive builder grade disposer that is just about good enough that they can say there is a disposer in the home when they sell it to you. The Badger series has a 1 – 3 year warranty depending on the model you have and I would not expect much more than 5 years of service out of it. The Badger series has a steel grinding chamber that is usually pretty well rusted away at that point and more than likely is sending food down the drain that has not been ground which can lead to clogging of the drain.

      I would recommend replacing rather than repairing the disposer. The cost of unclogging the drain will probably be higher than buying a new disposer so it makes sense to avoid possible trouble. I would suggest upgrading to an Insinkerator Evolution Series Disposer rather than the Badger especially if you plan on being in the home longer than 4 or, 5 years. The Evolution units are substantially quieter, have higher horsepower, and have stainless steel grind chambers giving them substantially longer service life.

      You can see some of my reviews on them at this link.


  5. Bob Knapp says:

    Have an ISE Heavy Duty about 15 years or older. The thing literally SCREAMS when on and, although it grinds, it will stop after a few seconds. I can turn it with the wrench and reset but it still does the same. Sounds like a foreign object, but none is apparent in the disposer and, like I said, it does grind. My initial impression is that I need a replacement. What do you think?
    Thanks, Bob

  6. dan says:

    I have a insinkerator excel, it has a small screw stuck on the fly wheel. I would like to see a way to open it or diagram, maybe one or two tips on how to open it. $300 is not a cheap price to pay each time something like this happens. I don’t think the warranty covers such accidents.

    • Redwood says:

      Hi Dan,

      Your best bet is probably to undo the locking collar and drop the unit down from the sink flange. You will then be able to remove the rubber inlet cover and see into the unit better. Look for the screw to be wedged in the crack between the turntable and the side wall of the unit. They are small so they will be tough to see and a pair of long needle-nose pliers or forceps will probably be needed to grab the screw.


  7. Brian says:

    I have an insinkerator evolution compact with a motor that continues to run even after switching the on/off switch to off. I can only turn the unit off/on by way of the circuit breaker. The red reset button does not turn it off either. This unit was installed probably about 4-5 years ago.

    • Redwood says:

      Hi Brian,
      Do you have the Insinkerator countertop switch or, a wall switch?

      • Brian says:

        Sorry I took so long Redwood, the wall switch is installed in the cabinet under the sink

        • Redwood says:

          Hi Brian,
          Make sure the switch is correctly installed and the “Hot” is being switched not the “Neutral.”
          If the switch is installed correctly then the switch needs replacing. If the switch is not correctly installed then there may be other problems as well.

  8. Jane says:

    I have a problem no one, not even the manufacturer seems to have heard of before. The developers of my building installed an Insinkerator 45 air under my sink back in 2005. I have hardly ever used the thing. Then this morning I opened the under sink cupboard to find that the plastic had cracked and then sheared through. The top half of the device is still attached to the sink and the waste pipe, but the heavy metal bit with the grinding discs had completely broken off and was lying on the floor of the cupboard, still live electrically as all the wires are attached to the broken half. First why on earth did this happen? Is it normal? Have you ever heard of it before? Second, could either my failure to use is (maybe half a dozen times in five years) and/or the very hard water in London have anything to do with it splitting in half. Finally, if this has happened to one model is it safe to install a replascement. Thank you for your attention

    • Redwood says:

      Hi Jane,
      The Insinkerator 45 is a low end unit that is commonly installed by builders along with the Insinkerator Badger 1 & Badger 5 which is the similar unit sold in the US. These disposers have a galvanized steel rotating shredder and shredder ring, which while it is corrosion resistant is far from corrosion proof, so these units only have a 2 year warranty. At 7 years of age it has lasted far longer than it was designed for. These units typically sell for around $70 (45£) and really are little more than a disposable disposer that enables a developer to say that the kitchen in your apartment has a disposer.

      The infrequent use may have been a factor as the shredder ring often acts as a strainer and may plug with debris which is only cleared by running the unit and water may hold on the grind chamber accelerating the corrosion rate. The corrosion may have caused a swelling which caused the case to split or, the corroded parts may have bonded together shearing the unit when it was turned on. There may also have been a foreign object dropped into the unit which sheared the case when the disposer tried to grind the object. It is hard to say without knowing more.

      In any case you are either due for purchasing another disposer or, redoing the sink drain and eliminating the disposer. I have done both of these tasks for my customers depending on their wishes. If you do wish to install a new disposer and intend to live in that location for longer than the expected life of the lower end disposers I would suggest an upgrade to a more expensive unit that utilizes a stainless steel rotating shredder and shredder ring.


  9. Keith says:

    Hi, you’re providing some great info, so I’ll ask you for some more. :-). I inherited a Badger 5 that has a crack and needs to be replaced. I got an Insinkerator Evolution, and it looks awesome, but I have a plumbing question. The previous homeowner had a simple straight line from the disposal to the wall (no trap), and I think I should put a trap in. It’s a single sink, so it should be fairly simple, no? Just buy the PVC trap and a pipe long enough to connect the wall, connector bits, and make sure it’s the right diameter?

  10. Kurt says:


    I am writing because after using a knife to clear away ungrounded food that had encrusted along the inside of my Insinkerator unit, I developed a leak even when not in use with just water flowing into the sink.

    Initially I figured I must have punctured dome sort of seal, or gasket. After putting it on the “To Do” list I figure I would check to see if there were any gasket/repair kits at my local Home Depot.

    Well that was almost three years ago and I have yet to fix or replace it. Although, I did look for Repair Kits, I was unsuccessful in finding any, and so life without a disposal had not been a priority …..until now.

    It being the Holidays, I had some free time and I figure I would check the internet for a Replacement Kit. I just went to my disposal to get the Model Number, an low and behold, I discovered a Barnacle-like growth all around the outside of my disposal. It is an Insinkerator Model 5-38A. I have no idea how old it is, but I have been in this home for at least 13 years, and the house was built in 1978. And so for all I know this disposal is 30 years old.

    There is no convincing me that I need a new disposal. I just wanted to share my story, and let you know that I appreciate the forum you have setup here to give people feedback and tips on installation. I have no doubt that I will be visiting again soon after I get my new unit.

    I will close here and look into one of the new Insinkerator models at Home Depot.

    Best regards,


    • Redwood says:

      Hi Kurt,

      It’s pretty clear that this Insinkerator Leak Repair Kit is just what you need. The Insinkerator Model 5-38 is the Badger 5 Disposal, which is the cheap “Builder Grade” unit only carried a 2 year warranty, and by the time it was 5 years old was probably shot. Since you’ve let it leak for 3 years without fixing it, obviously the best choice for you would be a model that lasts a little longer than the “El-Cheapo” builder grade unit, so you won’t have to replace it again any time soon.

      The “Barnacle-Like” growth is corrosion of the die cast metal body of the disposer, and I’m surprised it hasn’t just fallen off the sink yet, breaking the pipes out of the wall, when it went. The odds of it being 30 years old are pretty slim, more than likely it was a new unit shortly before you purchased the house. They just wouldn’t make it that far! You have better odds of hitting Power Ball 3 times than that happening.

      With it leaking for 3 years I wonder about the amount of damage that the leaking water has done on your cabinets, floor and walls in the area surrounding the kitchen sink. There is no doubt that there is a lot of rot and mold in the area along with who knows what kind of bacteria growing. It must smell pretty good in the cabinet under the sink, maybe time for a kitchen remodel as well?

      Good luck with your project,

      • John says:

        Hi Everyone…I have a Evolution Compact less than 2 years old. One of those things where
        it woked one day and not the next. Tried the reset. Tried the safety wall switch buttons and
        nothing. I’m about to see if the wheel is stuck??
        Unit is a little over a year old.

        Thanks for any help

        • Redwood says:

          Hi John,
          I always start with the fast and easy checks first:

          • Use the wrench in the bottom, does the wheel spin freely or, is it jammed? If jammed I unjam the wheel and remove the offending object causing the jam.
          • Is the red reset button popped? This usually happens after a jam, in which case I reset the button by pressing it.

          Usually this first step will get the disposer running again. If it doesn’t then it is time to take the troubleshooting to the next level:

          • When the unit is turned on do you get a humming noise? If so recheck that the wheel turns freely, if the wheel is not turning freely recheck for an object jamming the wheel and remove it. If the wheel spins freely then the motor has a problem and you need to call Insinkerator to take advantage of their In-Home Service Warranty.
          • If nothing happens when the unit is turned on then you need to open the cover on the bottom of the unit and check for power being supplied to the motor leads with a test light or, multimeter. If power is supplied to the motor leads then the unit has failed and it is time to call Insinkerator to take advantage of their In-Home Service Warranty. If there is no power supplied then you need to trace the circuit backwards all the way to the circuit breaker panel if need be, and find where there is a bad connection causing the loss of power to the unit.

          Hopefully this helps you out,

  11. Thom says:

    My Badger.5 Plus Insinkerator keeps throwing the GCFI. It has worked fine for 3 years, just started doing this. Why?

    • Redwood says:

      Hi Thom,
      The GFCI reads the current used on the circuit and the current being used from the “Hot” wire must match the current on the “Neutral” wire or, the GFCI will trip. Either there is a path for current leakage in the wires supplying the Badger 5 or, there is one internal within the Badger 5.

      I’d suspect the Badger 5 having the internal ground fault as the most likely problem but you may check by turning the power off to the Badger 5, then opening the cover on the bottom, removing the wires and disconnecting them. Once that is done turn the power back on to the Badger 5 and see if the GFCI still trips.

      If the Badger 5 is the cause of the GFCI tripping as I suspect it is, discontinue use, and replace it ASAP as the Ground Fault is a dangerous situation and the GFCI is protecting the user from electric shock. There are no user serviceable parts inside the Badger 5.


  12. Kevin says:

    I have a insinkerator excel that is a little over 3 yrs old,the turntable turns freely but all it does is hum when turned on. what is the average life expectancy of these units

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