In short
Installing a disposer in a flat in an apartment building is like installing a dishwasher or a washing machine: it connects to the sink drain and to the power supply, and no permission is needed. What really matters is that the drain works well, and we check that during the site visit.
Is it allowed?
Yes. An apartment building follows the same rules as any other installation: national law, art. 107(3) of Legislative Decree 152/2006, allows food scraps reduced to fine particles by a disposer to go into the sewer, where the network is connected to a treatment plant. For your address, everything is on the «Check your area» page.
Do you need the building's permission?
No. Using the shared drain stack for the sink and appliances is a right of every owner: the Italian civil code allows each co-owner to use the common parts, provided they do not change their purpose or prevent the others from using them in the same way (art. 1102 of the civil code). A disposer changes neither: it discharges water carrying food particles fine enough that InSinkErator declares them compatible with drains.
In almost fifty years of work we have never come across building rules that banned disposers.
It is different if work is needed on the shared stack itself, for instance replacing a section: that goes through the building manager, like any work on common parts. But it has nothing to do with installing the disposer.
Can the drain stack cope?
It is the question we are asked most often, especially in buildings with old cast-iron stacks. In the great majority of cases the answer is yes.
Cast-iron stacks have been in place for almost a century and still work. Their inner surface is rougher than plastic pipe and does not help the flow, but it has done the job for generations. When a cast-iron stack breaks or cracks, it is a matter of age, wear and the stiffness of the material, not of what flows through it.
Long horizontal runs work if they are properly built, although they are best avoided.
There is an example close to home: in the early 1970s the San Felice district, a large residential complex spanning Segrate, Peschiera Borromeo and Pioltello, fitted disposers as standard in the flats it sold furnished. And the stacks were cast iron.
There is just one rule: if the drain is well built, the disposer works well. If it is badly built, the problem is already there, with or without a disposer.
What we check on the site visit
That the drain is not blocked: we fill the sink bowl completely and watch how it empties. The time and the flow must be right.
That the drain can breathe: if you hear gurgling as the water goes down, or the sink backs up, the drain is not vented enough. In that case we fit an air admittance valve, which is worth having anyway, with or without a disposer.
The space under the sink, the power socket and the control, to choose the right solution.
When we advise against it
We advise against installation when the drain is badly built: in an apartment building, a house or any other building. If the drain is slow, if you tell us it blocks often, or if it has any other problem, a disposer could not work as it should, and there would be no point adding one.
In those cases we suggest fixing the drain first and then getting back in touch. Or we fix it ourselves, as part of the same job.
Noise and neighbours
A disposer makes the noise of an ordinary appliance, for a few seconds at a time. The same common sense applies as for a dishwasher or a blender: use it at reasonable times, with consideration for the neighbours.
The electrical side
In most kitchens the electrical installation does not need to be touched.
The first solution is the pneumatic air switch supplied with the EC and SR models: a button on the worktop or the sink. You simply plug the disposer into the socket under the sink: no changes to the wiring, no certificate.
The second is the remote control, available as an accessory: the plug goes into the socket through the remote-controlled adapter. Again, no changes and no certificate.
If there is no socket under the sink, or you want a wall switch, the electrical installation has to be modified: that work must be done to standard and certified with a declaration of conformity (Ministerial Decree 37/2008).
Notifying the water operator
When we supply and install the disposer, we notify the water service operator ourselves. All the details are on the «Utility notification» page.
How we work in Milan and its province
A site visit to check the drain, the space and the power supply. A written quote, with separate lines for the appliance and the installation. Installation, including notification to the water operator. Clean-up and test: the sink filled, the drain checked, the disposer run in front of you.