# What is a "garbage disposal unit"? **URL:** \ **Category:** Factual Questions\ **Created:** [December 4, 2004, 10:20pm UTC](https://boards.straightdope.com/t/what-is-a-garbage-disposal-unit/278115 "2004-12-04T22:20:13Z")\ **Posts on this page:** 20\ **Page:** 2
**Author:** ![WhyNot](https://avatars.discourse-cdn.com/v4/letter/w/c77e96/32.png) [@WhyNot](https://boards.straightdope.com/u/WhyNot)\ **Post date:** [December 5, 2004, 1:35am UTC](https://boards.straightdope.com/t/what-is-a-garbage-disposal-unit/278115/21 "2004-12-05T01:35:26Z")
> [@NattoGuy](#): > > A garbage disposal unit’s job is to force sink-water down the drain. The intended usage is to force drainage of sink-water contaminated with soft food or small amounts of fibrous or hard food. (For example, dishes covered with uneaten mashed potatoes and a few green beans would be OK). > > Contrary to popular belief, you aren’t supposed to rely on your garbage disposal to chop food. They aren’t terribly good at food-chopping. Fibrous material like carrot peelings will easily clog the impeller, forcing you to learn all of this the hard way (like I did). Rely on your garbage disposal ONLY to force sink water with soft food particles down the drain. I’ve never jammed up a garbage disposal, and I’ve done some pretty heinous things to it in the name of fun. Maybe yours is underpowered? > [@](#): > > Sink disposal units are bad for the water treatment system in so many ways. They introduce excess loads of minerals, organics, and BOD (biological oxygen demand) into the water treatment system. Ok, I hear what you’re saying, I really do, and excuse me if this is TMI. But, umm, what about the “fibrous” material that goes undigested and ends up down my other drain - the one in the littlest room? There’s lots of color some mornings. Things aren’t all that chopped up, ifyouknowwhatImean. And the sewers outside get lots of leaves, twigs, cig butts, potato chip bags and other much larger particles going into them. Sewage Treatment facilities have [screens and filters](http://www.dcs.exeter.ac.uk/water/sewage.htm) to get this stuff out - why not food particles? After all, the stuff in the littlest room is food particles, too - just in a different form. ---
**Author:** ![Early\_Out](https://avatars.discourse-cdn.com/v4/letter/e/6f9a4e/32.png) [@Early\_Out](https://boards.straightdope.com/u/Early_Out)\ **Post date:** [December 5, 2004, 1:39am UTC](https://boards.straightdope.com/t/what-is-a-garbage-disposal-unit/278115/22 "2004-12-05T01:39:57Z")
> [@Chefguy](#): > > Nor do most people understand that one must run copious amounts of hot water after the debris to make sure it clears your laterals. The [user manual for the In-Sink-Erator](http://www.insinkerator.com/pdf/US_ICU1.pdf) specifically says to use cold water, not hot. I’m not sure why. Of course, they also tell you not to pour grease down the sucker in the first place. They also maintain that it’s [environmentally more friendly](http://www.insinkerator.com/h_environment.html) to send food waste to the sewage treatment plant than to the landfill (they don’t mention composting, of course). I’m not sure I buy that one. ---
**Author:** ![WhyNot](https://avatars.discourse-cdn.com/v4/letter/w/c77e96/32.png) [@WhyNot](https://boards.straightdope.com/u/WhyNot)\ **Post date:** [December 5, 2004, 1:44am UTC](https://boards.straightdope.com/t/what-is-a-garbage-disposal-unit/278115/23 "2004-12-05T01:44:03Z")
> [@Early Out](#): > > The [user manual for the In-Sink-Erator](http://www.insinkerator.com/pdf/US_ICU1.pdf) specifically says to use cold water, not hot. I’m not sure why. Of course, they also tell you not to pour grease down the sucker in the first place. > > They also maintain that it’s [environmentally more friendly](http://www.insinkerator.com/h_environment.html) to send food waste to the sewage treatment plant than to the landfill (they don’t mention composting, of course). I’m not sure I buy that one. WAGging: If we all chopped up our food waste into little bitty bits and sent it through the sewers to be strained out and sent to the landfill from there (as it is) then the pieces are tiny, some decomposition has already ocurred, and the volume of waste is decreased, simply because the pieces are smaller and fit together more tightly. Less air space in the landfills. Not as good as composting, but better than throwing huge chunks of carrot in a plastic bag. ---
**Author:** ![jnglmassiv](https://avatars.discourse-cdn.com/v4/letter/j/f07891/32.png) [@jnglmassiv](https://boards.straightdope.com/u/jnglmassiv)\ **Post date:** [December 5, 2004, 1:46am UTC](https://boards.straightdope.com/t/what-is-a-garbage-disposal-unit/278115/24 "2004-12-05T01:46:48Z")
I can’t be the only one here who has had to fish bits of shredded coins and pretzel’d flatware from thses things. The one’s I’m familiar with really do dispose of anything you intentionally throw down them. ---
**Author:** ![HMS\_Irruncible](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/hms_irruncible/32/7394_2.png) [@HMS\_Irruncible](https://boards.straightdope.com/u/HMS_Irruncible)\ **Post date:** [December 5, 2004, 2:29am UTC](https://boards.straightdope.com/t/what-is-a-garbage-disposal-unit/278115/25 "2004-12-05T02:29:24Z")
The rotating unit in the “insinkerator” is called an “impeller.” It is designed to force water down the drain. By design, an aquatic impeller does of course contain blades, but their primary purpose is to increase the water pressure in the drain, not to chop waste. They aren’t made to chop waste finely enough to handle large amounts of waste. In fact, if you refer to the insinkerator manual, you can see a diagram of the blades showing this fact. You can also see an admonition that some hard food material needs to be pre-chopped, and you shouldn’t put large amounts of fibrous or vegetable material into the disposal. I was just as surprised as you to hear it; I had always considered it a food processor for waste until I had one choke on carrot peelings. I didn’t invent these facts, go argue with the Insinkerator people if you don’t believe me. [http://www.insinkerator.com/pdf/US\_ICU1.pdf](http://www.insinkerator.com/pdf/US_ICU1.pdf) ---
**Author:** ![WhyNot](https://avatars.discourse-cdn.com/v4/letter/w/c77e96/32.png) [@WhyNot](https://boards.straightdope.com/u/WhyNot)\ **Post date:** [December 5, 2004, 2:39am UTC](https://boards.straightdope.com/t/what-is-a-garbage-disposal-unit/278115/26 "2004-12-05T02:39:44Z")
> [@NattoGuy](#): > > I didn’t invent these facts, go argue with the Insinkerator people if you don’t believe me. > [http://www.insinkerator.com/pdf/US\_ICU1.pdf](http://www.insinkerator.com/pdf/US_ICU1.pdf) I did read it, here’s what it says: > [@](#): > > **DO…** > • First turn on a moderate to strong flow of cold water and then turn on the disposer. Continue running cold water for 15 seconds after grinding is completed to flush the drain line. > **• Grind hard materials such as small bones, fruit pits, and ice. A scouring action is created by the particles inside the grind chamber.** > • Grind peelings from citrus fruits to freshen up drain smells. > • Use a disposer cleaner, degreaser, or deodorizer as necessary to relieve objectionable odors caused by grease build-up. > \*\* > DON’T…\*\* > • Don’t pour grease or fat down your disposer or any drain. It can build up in pipes and cause drain blockages. Put grease in a jar or can and dispose in the > trash. > • Don’t use hot water when grinding food waste. It is OK to drain hot water into the disposer between grinding periods. > • **Don’t fill disposer with a lot of vegetable peels all at once. Instead, turn the water and disposer on first and then feed the peels in gradually.** > **• Don’t grind extremely fibrous materials like corn husks, artichokes, etc., to avoid possible drain blockage.** > • Don’t turn off disposer until grinding is completed and only sound of motor and water is heard. > • Don’t be alarmed if a brown discoloration appears on the face of the grinding disc. This is normal. It is surface discoloration only and will not affect the life or > performance of the disposer. (bolding mine)I think you’re being overly cautious. Carrot peels should not have gummed up the works unless you packed it tight before running it. I mean, the thing is called an “Insinkerator FOOD WASTE DISPOSER,” for goodness’ sake. ---
**Author:** ![violacrane](https://avatars.discourse-cdn.com/v4/letter/v/c57346/32.png) [@violacrane](https://boards.straightdope.com/u/violacrane)\ **Post date:** [December 5, 2004, 3:22am UTC](https://boards.straightdope.com/t/what-is-a-garbage-disposal-unit/278115/27 "2004-12-05T03:22:52Z")
Good to see so many composters here 🆒 I missed this bit in Kymodyce’s reply: > [@](#): > > most useful for foodstuffs which will putresce rather than compost Oops. Supplementary garbage question: it almost seems a given in US culture that taking out the trash is a big deal, with reference to it being a chore for teenage boys and husbands in particular, what’s with that? If it’s any help my dustbin is just outside the back door, the binmen used to fetch it and bring it back but now I have a wheelie bin which I take to the roadside myself. ---
**Author:** ![Shagnasty](https://avatars.discourse-cdn.com/v4/letter/s/9dc877/32.png) [@Shagnasty](https://boards.straightdope.com/u/Shagnasty)\ **Post date:** [December 5, 2004, 3:31am UTC](https://boards.straightdope.com/t/what-is-a-garbage-disposal-unit/278115/28 "2004-12-05T03:31:46Z")
> [@violacrane](#): > > Good to see so many composters here 🆒 I missed this bit in Kymodyce’s reply: Oops. Supplementary garbage question: it almost seems a given in US culture that taking out the trash is a big deal, with reference to it being a chore for teenage boys and husbands in particular, what’s with that? If it’s any help my dustbin is just outside the back door, the binmen used to fetch it and bring it back but now I have a wheelie bin which I take to the roadside myself. Isn’t so much about taking out the trash. It is about making it easier to do dishes. You throw dishes with food still on them in the sink, turn on the water to rinse the food down the drain, and then hit the garbage disposal switch. Then you throw the dishes in the dishwasher and turn that on and go watch TV. Now wasn’t that easy. ---
**Author:** ![Shagnasty](https://avatars.discourse-cdn.com/v4/letter/s/9dc877/32.png) [@Shagnasty](https://boards.straightdope.com/u/Shagnasty)\ **Post date:** [December 5, 2004, 3:34am UTC](https://boards.straightdope.com/t/what-is-a-garbage-disposal-unit/278115/29 "2004-12-05T03:34:24Z")
> [@violacrane](#): > > Good to see so many composters here 🆒 I missed this bit in Kymodyce’s reply: Oops. Supplementary garbage question: it almost seems a given in US culture that taking out the trash is a big deal, with reference to it being a chore for teenage boys and husbands in particular, what’s with that? If it’s any help my dustbin is just outside the back door, the binmen used to fetch it and bring it back but now I have a wheelie bin which I take to the roadside myself. Oh, I see that I didn’t answer your question quite right. The answers vary but factors are that Americans ten to generate a whole lot of trash so you could be looking at some oversized 40 pound Hefty bags there, and many Americans have large yards and it could be a walk. Please, we are lazy as shit. ---
**Author:** ![violacrane](https://avatars.discourse-cdn.com/v4/letter/v/c57346/32.png) [@violacrane](https://boards.straightdope.com/u/violacrane)\ **Post date:** [December 5, 2004, 3:52am UTC](https://boards.straightdope.com/t/what-is-a-garbage-disposal-unit/278115/30 "2004-12-05T03:52:26Z")
Aah, laziness, yes, I understand laziness. ---
**Author:** ![Hunter\_Hawk](https://avatars.discourse-cdn.com/v4/letter/h/50afbb/32.png) [@Hunter\_Hawk](https://boards.straightdope.com/u/Hunter_Hawk)\ **Post date:** [December 5, 2004, 4:05am UTC](https://boards.straightdope.com/t/what-is-a-garbage-disposal-unit/278115/31 "2004-12-05T04:05:19Z")
I have relatives in Hawaii (I forget the exact place, but it’s across the island from Honolulu), and they said that garbage disposal units were _required_ there. The authorities didn’t want people to throw out or compost food waste due to concerns about insects, particularly cockroaches. ---
**Author:** ![WhyNot](https://avatars.discourse-cdn.com/v4/letter/w/c77e96/32.png) [@WhyNot](https://boards.straightdope.com/u/WhyNot)\ **Post date:** [December 5, 2004, 4:29am UTC](https://boards.straightdope.com/t/what-is-a-garbage-disposal-unit/278115/32 "2004-12-05T04:29:49Z")
> [@violacrane](#): > > Good to see so many composters here 🆒 I missed this bit in Kymodyce’s reply: Oops. Supplementary garbage question: it almost seems a given in US culture that taking out the trash is a big deal, with reference to it being a chore for teenage boys and husbands in particular, what’s with that? If it’s any help my dustbin is just outside the back door, the binmen used to fetch it and bring it back but now I have a wheelie bin which I take to the roadside myself. We also tend to use huge honkin’ trash bins in our kitchens here. Ours holds a 30 gallon bag. So stuff tends to sit around and putresce (my new favorite word!) for the week or so we’re filling the huge container before we take it out. Eeew. But living on the third floor with rickety steps leading down to the dumpster, it’s not something I like doing often. ---
**Author:** ![mangeorge](https://avatars.discourse-cdn.com/v4/letter/m/d78d45/32.png) [@mangeorge](https://boards.straightdope.com/u/mangeorge)\ **Post date:** [December 5, 2004, 4:46am UTC](https://boards.straightdope.com/t/what-is-a-garbage-disposal-unit/278115/33 "2004-12-05T04:46:49Z")
😃 Anyway; > [@WhyNot](#): > > We also tend to use huge honkin’ trash bins in our kitchens here. Ours holds a 30 gallon bag. So stuff tends to sit around and putresce (my new favorite word!) for the week or so we’re filling the huge container before we take it out. Eeew. But living on the third floor with rickety steps leading down to the dumpster, it’s not something I like doing often. I once lived in an apt with the dumpster directly below my 3rd floor window. Beautiful. ---
**Author:** ![Diceman](https://avatars.discourse-cdn.com/v4/letter/d/22d042/32.png) [@Diceman](https://boards.straightdope.com/u/Diceman)\ **Post date:** [December 5, 2004, 5:37am UTC](https://boards.straightdope.com/t/what-is-a-garbage-disposal-unit/278115/34 "2004-12-05T05:37:25Z")
Also, there are people like my mother who overfill the garbage can, and then cram the garbage down and tie the bag off. Those bags are under a _lot_ of stress by the time she throws them out, and if you so much as look at that bag the wrong way, it’ll rip open. No, taking out the trash was not a fun chore when I was a kid. ---
**Author:** ![BobT](https://avatars.discourse-cdn.com/v4/letter/b/8e8cbc/32.png) [@BobT](https://boards.straightdope.com/u/BobT)\ **Post date:** [December 5, 2004, 6:03am UTC](https://boards.straightdope.com/t/what-is-a-garbage-disposal-unit/278115/35 "2004-12-05T06:03:54Z")
> [@friedo](#): > > Garbage disposals are illegal in New York City, due to the high demands of the city sewar system. Apparently there’s a thriving black market for them. > > Kramer had one in his shower. 🆒 The New York City Council allowed garbage disposals to be installed in New York City homes back in 1997. ---
**Author:** ![robby](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/robby/32/11048_2.png) [@robby](https://boards.straightdope.com/u/robby)\ **Post date:** [December 5, 2004, 7:07am UTC](https://boards.straightdope.com/t/what-is-a-garbage-disposal-unit/278115/36 "2004-12-05T07:07:58Z")
> [@Early Out](#): > > American municipal waste systems are robust enough to handle the extra load. No, they’re not. I’m an environmental engineer, and one of my specialties is wastewater collection and treatment. Actually, as populations increase and standards get more restrictive, many municipalities are looking for ways to postpone another expensive upgrade to their wastewater treatment facilities. One way is to encourage people NOT to use sink disposer units. Some towns here in Connecticut have even started banning them. If you have a septic system, it’s a even worse idea. You are just asking for your leach field to get clogged with food debris, and a leach field replacement goes for about $10K these days. The chance of this can be reduced by pumping your septic tank at least annually, but it’s still risky. Most of the engineers in my office have septic systems, and we have all flat-out told our spouses that they are never going to get a sink disposer system. 🙂 ---
**Author:** ![enipla](https://avatars.discourse-cdn.com/v4/letter/e/54ee81/32.png) [@enipla](https://boards.straightdope.com/u/enipla)\ **Post date:** [December 5, 2004, 2:25pm UTC](https://boards.straightdope.com/t/what-is-a-garbage-disposal-unit/278115/37 "2004-12-05T14:25:56Z")
I have one, and I’m on a septic system. 12 years No problems. I’ve had it pumped three times. The last time I pumped it was because I had to uncover it anyway, so what the heck. The other times I pumped was purely precautionary, I wasn’t having problems. I only use the disposer for what gets rinsed off plates before they get washed. So it’s not like I stuff trash down it. It’s just for cleaning up the little. And it’s great for that. ---
**Author:** ![Jurph](https://avatars.discourse-cdn.com/v4/letter/j/50afbb/32.png) [@Jurph](https://boards.straightdope.com/u/Jurph)\ **Post date:** [December 5, 2004, 3:06pm UTC](https://boards.straightdope.com/t/what-is-a-garbage-disposal-unit/278115/38 "2004-12-05T15:06:50Z")
> [@Chefguy](#): > > Nor do most people understand that one must run copious amounts of hot water after the debris to make sure it clears your laterals. > > Do yourself a favor and return the damn thing now. Trash is for the landfill, not the sanitary sewer. Two points: whether or not most people understand it or make a habit of it, many places that have one of these also have an automatic dishwasher, and every setup I’ve seen (3? 4?) has the dishwasher’s drainage line (hot soapy water) plumbed in upstream of the garbage disposal. That way when you run the dishwasher, the hot water clears out your disposal. Secondly – and this is from my lack of understanding of where the sink’s drain goes – surely it’s no worse for the waste processing plant than, say, feces? I know I should compost it, but I end up flushing most of my poop down the toilet. Does my house (city sewer) have two different drainage systems? ---
**Author:** ![enipla](https://avatars.discourse-cdn.com/v4/letter/e/54ee81/32.png) [@enipla](https://boards.straightdope.com/u/enipla)\ **Post date:** [December 5, 2004, 3:15pm UTC](https://boards.straightdope.com/t/what-is-a-garbage-disposal-unit/278115/39 "2004-12-05T15:15:50Z")
> [@Jurph](#): > > Does my house (city sewer) have two different drainage systems? Nope, it all goes to the same place. You brought up a good point, dishwashers discharge into the disposal. This allows an additional grinding of stuff left on plates. I’m not talking about lots of food, just little bits that did not get rinsed off before put in the dishwasher. ---
**Author:** ![scotandrsn](https://avatars.discourse-cdn.com/v4/letter/s/a4c791/32.png) [@scotandrsn](https://boards.straightdope.com/u/scotandrsn)\ **Post date:** [December 5, 2004, 3:25pm UTC](https://boards.straightdope.com/t/what-is-a-garbage-disposal-unit/278115/40 "2004-12-05T15:25:45Z")
> [@Aspidistra](#): > > What are these things? Why would you have one rather than just a rubbish bin? (which presumably you need anyway, for the rest of the rubbish) Does every house in the US have one? Any other countries have them, or is it just the US? And if so, why? I haven’t seen a good description of them yet, so here you are: Instead of a simple drain hole in the bottom of your kitchen sink, you have a powerful cylindrical motorized unit in between the sink drain and the waste pipe (most houses equipped for them will have an electrical hookup in the cabinet under the sink basin). A few bits of food didn’t get scraped into the trash, and clogged up your sink while you’re washing dishes? The disposer chops it up and your sink drains normally again. Saves time, effort, or a call to the plumber. That’s the origin of it, anyway. Since their introduction, people have found all sorts of uses for their disposal, requiring them to become more and more powerful. For instance, if the thing chops food, why scrape any food into the trash at all? Just put it down the disposal unit\*. Now you don’t have old food making your kitchen wastebasket or your outdoor trashcan stink until it gets emptied. Once the electric dishwasher got a foothold, it made sense to hook up its drain to the disposer, so that the dishwasher didn’t clog your sewer lines either. It’s common in real estate listings to see “modern kitchen with D/D” (dishwasher/disposal combination. My current dishwasher, even though it drains through my disposal, has its _own_ disposal unit built right into the bottom. \*But never, ever, EVER (as my wife can tell you from last year) put the peelings from five pounds of potatoes into it on Christmas Eve twenty minutes before the guests arrive. You will spend a waterless wreck of a holiday getting up-close-and-personal with the giant, reeking, disposal-julienned mess that has prevented all aqueous egress from your dwelling until the next normal business day when the plumber may not require the relinquishment of your first-born to come fix it. [Previous page](https://boards.straightdope.com/t/what-is-a-garbage-disposal-unit/278115.md?page=1) [Next page](https://boards.straightdope.com/t/what-is-a-garbage-disposal-unit/278115.md?page=3)