Sink disposal units aka insinkerators

Can anyone help me with Sink disposal units. Our ‘insinkerator’ brand is only 8 years old and is leaking badly within the unit, not the pipework. It’s not very good as constantly blocking but worth it as we live in an apartment.
Can anyone give me some idea of how good or bad their unit is please.
One thing I have discovered is that all the units in our apartment block have been badly plumbed as the ‘U’ bend below the unit has moulding fins inside the pipe instead of outside. So smooth on the outside and joint fins on the inside? If stainless steel had of been used there would not have been obstructions inside the drainage pipe to ‘sinkerated’ food.
Help please.


Welcome to the community @SDK

Our Insinkerator is 20 years old and has not missed a beat. Prior, we had one in the US that was 12 years old when we relocated to Melbourne, and before that another one. None ever needed service nor even a renewed rubber part in the drain.

Are you saying water is leaking from the unit itself?

It should never block if the plumbing is correct. Our pipework is plastic, no fins per se.

Not sure what advice to give excepting to contact Insinkerator Australia about the leak as it is unclear if you are the first own of the apartment, a subsequent owner, or a tenant.

The Insinkerator (garbage disposal) should be pulverising food waste, and it should be a slush as it goes into the drain. These units are ubiquitous in the USA and there are many tutorials and useful web sites. A starter might be to google ‘plumbing garbage disposal’ to see how it should be.

What help/advice do you seek?


Thanks for that. A manufacturer apart from insinkerator and your personal experience and cost of unit would be nice. Two owners and one tenant have lived here. The tenant only for a year. My brother has a unit that destroys everything put in it. This unit blocks with egg shells. I’m surprised and disappointed that Choice have not tested them especially with the thousands of apartments being built now. Cheers.


Apologies but not a fan!

We had one in a town house +(1980’s) and it was for ever creating problems, +(20 years installed). I’m not sure that it was a problem with the disposal unit. But what’s wrong with putting waste in the garbage like most households?

All units have garbage services. Is it an essential that a unit must have a device to turn the sink into a waste grinder?

We solved our repeated issue with tenants after replacing the unit twice by simply removing it. Perhaps the device is great for getting rid of potato peel rather than to compost, but lamb bones from the weekend roast?

Unfortunately for a rental, proving the failure of the waste disposal device is due to tenant malfunction may be too great an ask.

As @PhilT suggests in the hands of an experienced user such devices are irreplaceable.

‘+ edit notes added for some clarity on relevant experience. It looks as if we were ahead of the curve.


Having had none but Insinkerators in living memory. For environmental reasons they did not seem to catch on in Australia until comparatively recently, in the era of ‘modern flats’.

Prices 20 years ago would not be a guide. Google ‘garbage waste disposals Australia’ or check AppliancesOnline, Bunnings, and TheGoodGuys for Insinkerator prices. Franke and a few others also have products that will be represented in the hits if you are patient to troll through them all.

There are many brands sold in the US but locally if you need parts and support, from googling there are not many choices, to be kind.

Be wary about any electrical product coming from the USA because they will probably be 110-120V 50-60Hz, inappropriate for Australia because of electrical supply or standards compliance.


No offence, but I presume you run the cold water smartly while grinding? The cold water supports creating the slush as well as cooling the blades while in operation.


Not only environmental reasons. If one has a damaged sewer, partial blockage (e.g. root or other minor obstruction) or slow gradient pipes, a insinkerator can give a lot of grief causing buildups in pipes leading to blockages.

About 20 years ago I worked briefly for a council where the Council’s waste water operators requested advice whether they could be banned in the local area. The reason is food macerated by these devices cause main sewer blockages and also increase materials removed from prescreening of black water at treatment plants (in effect it pushes waste disposal of the materials to councils, rather than materials being placed in a bin). The screened out materials ending up in landfill.

Council as a whole was keen to ban new installations but the advice was a whole of state approach was needed (as one could buy and install using tradie/retailer in adjacent council. The state government at the time didn’t have the appetite to ban them.

They may not be as good as they initially seem.


Or better still in the compost, most of what goes down is compostable. I know an individual compost bin may not be practical in high rise living. Perhaps the builders of such accommodation could spend the money on group compost collection instead of a sink grinder in every unit. A silly idea I know but loading the sewerage system with material that does not need sewerage processing and wasting potable water to flush it is sillier.


I have never heard of this (edit: I am assuming that this is the standard rigid PVC drain piping), but I would be replacing those pipes forthwith with ‘normal’ pipes that have a smooth interior. I would suggest the fins could cause obstruction, especially if larger pieces escaped through the Insinkerator, as can happen.

When we lived in an apartment complex, we were given the Body Corporate’s permission to bury our compost in the garden. After a while, other residents were also contributing their compostable material as well. This meant that we and many residents stopped using the installed Insinkerator and also saved the Body Corporate some money on the water bill, and we contributed to the improvement of the garden. As a side issue, many fruit trees ended up growing from stones/seeds we buried in the garden.


I have seen some pipes with 1~2mm internal fin-like reinforcing barbs, and I presumed that is what was meant.

If the ‘fins’ are more than reinforcements it would indeed be unusual.

If the ‘fins’ mean a bendable pipe with a convoluted section, that would not be on under a disposal unit or possibly anywhere else as good practice.


It’s part of the injection moulding process - they could change the injection mould design so the ‘S’ bend had the ‘fins’ were on the outside but that would not look nice! That is why I would use stainless steel from now on. The problem still remains - I am looking for someone to recommend a better ‘insinkerator’ than we have now.


I’m curious.

Do you have a photo of the fins?
I’m not doubting your observation, but something in the communication seems to be missing.

The S/P traps for a basin or sink I’ve needed to do basic maintenance on has no fins inside or out. The fittings are totally smooth. It’s not clear that there needs to be a design change.


We have a Kitchen Aid “Superba” waste disposal unit (aka a TOL Insinkerator in Oz) that dates from the 1970’s and was was finally installed and used daily in our house now for the past 22 years and has never blocked or stopped or leaked. Was made by Hobart the commercial food equipment brand in the day - hence well built. To your question - there is daylight between the “entry level” units and the “top of the line” models and suggest if you head to the premier model from Insinkerator (Evolution 200) you may see many problem free years ahead. The other aspect is that Insinkerator are dominant in the Australian market (like Kitchen Aid back last century) so service may be better. If and when our unit “pegs out” likely we would replace it with Insinkerator as Kitchen Aid waste disposal division was sold to Emerson (Insinkerator) - again last century


Dear pmathieson, Thank you so much for this.
It is really appreciated.
I will take all into account.


No offence taken BBG. Yes, always use what we think is sufficient water. Have even tried using lots of water. It just builds up in base of the ‘S’ bend. 90% of blockages seem to be OK with a teaspoon of detergent and left overnight which clears things. Other blockages removed with suction applied with a plunger whilst running. The worst removed with removal of the ‘S’ bend. Time to clime up a model as research shows this model ‘45’ replaced by ‘46’ and it is the el cheapo developer model.