Frequently asked questions
Food waste disposers: the questions we are asked most often.
These are the questions people actually ask us, in the kitchen and on the phone. Short answers; where a number is needed, the source is there.
Can it be installed? Law, area, home
- Are food waste disposers legal in Italy? And in Milan?
- Yes, Italian law allows them (Article 107(3), Legislative Decree 152/2006) on one condition: that the drain reaches a water service treatment plant. That is why, before installing, we check the area and the drain: the operator is MM in Milan, Gruppo CAP across most of the province. If we install it, after installation the notification to the operator required by law is made by us; for purchases with shipping it is the buyer's responsibility.
- I have a septic tank, or I am not connected to the sewer. Is it possible?
- As a rule, no. The law allows disposers where the drain reaches a treatment system ascertained by the water service operator: a septic tank or a drain not connected to the public sewer does not fall into that case. Without that check we do not install.
- I live in an apartment building. Is it possible?
- Generally yes. First we check the building's drain stack and the building rules, if any: better to know beforehand. We answer after the site visit, not from a distance.
- Do you install throughout Milan and its province?
- Yes: in Milan and in the 133 municipalities of the Metropolitan City. Type your municipality in the checker below and we will also tell you who runs the water service and the treatment plant in your area.
Your kitchen and the installation
- Can it be fitted in an existing kitchen? What is needed?
- Yes, you do not need a new kitchen. Three things are needed: enough space under the sink, a compatible drain and a power supply with its control. We check that first, quickly.
- Will it fit my sink?
- In most sinks, yes: the disposer connects to the existing drain opening, whose diameter we check. Send us a photo of the sink and one of the cabinet below and we will tell you.
- I have a double-bowl sink.
- No problem: the disposer goes on one bowl and the drain of the other is connected to it.
- Is a power socket needed under the sink?
- Yes: a dedicated power supply and a safe control are needed, for example a switch or an air switch on the worktop. We do electrical work too: where the supply and the control have to be created, we build them ourselves, with the declaration of conformity required by Ministerial Decree 37/2008. Any cost for that is set out in the quote.
- Is it complicated to install? How long does it take?
- For a professional it is a simple installation. If the kitchen needs no particular changes, the job is quick and the work stays under the sink: no half-kitchen rebuild.
- Many plumbers advise against it. Why don't you?
- We have been plumbers since 1977. Usually the people who advise against it have seen one badly fitted, or fitted on old drains that were never checked. We check the plumbing first, then decide whether it can be done, or suggest the changes needed. In our experience the installation is very often feasible.
Using it every day
- How exactly do you use it?
- Turn on the cold water, switch it on, feed the scraps in a little at a time, wait until it has finished grinding, switch off and let the water run for another ten seconds or so. That is the sequence the manufacturer indicates.
- Hot or cold water?
- Always cold. The small traces of fat in the scraps stay solid, get ground and carried away, instead of melting and settling further along the pipes.
- What can I put in it?
- Kitchen scraps: peel, leftovers from plates, fruit and vegetables, pasta and rice in plate-sized amounts, bread, coffee grounds, eggshells. The more powerful models also grind small bones and stones. The simple rule: food scraps yes, everything else no.
- And what should never go in?
- Oil and fat, mussel and clam shells, and anything that is not food: plastic, glass, metal, rubber bands, matches, cigarette ends, fruit stickers. Very fibrous vegetables, such as celery, should go in cut up and a little at a time, not in a bunch.
- Can I pour frying oil into it?
- No. Oil must never go down the drain, with or without a disposer: collect it and take it to your municipality's collection points.
- Coffee grounds, really?
- Yes, in the normal amounts of a home kitchen.
- And eggshells?
- Yes.
- How much less food waste ends up in the bin? Can I get rid of it?
- A good share of food scraps goes straight down the sink, and the bag full of leftovers after dinner is gone: that is the difference people notice most. The bin does not disappear entirely, though: it stays for what the disposer does not handle and for your municipality's collection rules.
Safety, noise, odours
- Are there blades? Is it dangerous with children around?
- It has no blades like a blender, so there are no blades to sharpen: it grinds by rotation, pushing the scraps against a ring. As with any appliance, hands never go in while it is running.
- A teaspoon fell in. What do I do?
- Switch it off and cut the power, then retrieve it with pliers. Never by hand.
- Is it noisy?
- It only makes noise for the few seconds it is grinding. The top models are sound-insulated.
- Does it smell afterwards?
- On the contrary: the scraps do not sit in a bin under the sink, they go straight down the drain with the water. Just let the water run for a few seconds after use.
Pipes, cleaning and maintenance
- Can it clog the pipes?
- If it is installed correctly and used properly, no: it reduces leftovers to very small particles that the water carries away. The problem is not the disposer, but a bad installation, an old drain that was never checked, or incorrect use. That is why we check the plumbing first.
- Does it need maintenance?
- Very little. No filter to empty, no container to wash: just use it properly and keep it clean.
- Does citrus peel freshen it up?
- A little, yes: a few slices of lemon or lime are among the manufacturer's tips for cleaning it and removing odours. No magic, but it helps.
- Does ice clean it?
- The manufacturer suggests a few ice cubes to loosen residue from the chamber walls. Follow your model's manual in any case.
- Can I use bleach or drain cleaners?
- Follow your model's user manual. Harsh chemical drain cleaners should not be used; if the drain is slow, call us.
Consumption and the environment
- Does it use a lot of water?
- Little: between 3 and 4 litres per person per day, that is the cold water running while it grinds. Sources: University of Sheffield (2026) and the distributor's data sheet.
- And electricity?
- Very little, because it works for a few seconds a day: about 1.4–1.6 kWh per person per year (University of Sheffield, 2026). For a family of three that is little more than one euro a year, at the July 2026 ARERA reference tariff (31.63 c€/kWh).
- Is it better for the environment than separate food waste collection?
- It depends on the indicator. The University of Sheffield study (2026) finds it better than separate food waste collection on 14 indicators out of 18 and worse on 4, climate change among them; on that point the result depends on the treatment plant receiving the scraps. That is why we do not present it as a choice "for the climate". In Milan, where food waste is already collected well, the disposer works alongside collection rather than replacing it.
- Where do the scraps I send down the sink end up?
- They reach the treatment plant with the wastewater. Where the plant has anaerobic digestion — for example Bresso–Niguarda, run by Gruppo CAP — they contribute to producing biogas and biomethane; at the Nosedo plant (Milan) that section is planned for the coming years.
- Is there a TARI discount in Milan for having a disposer?
- As at the date of this page, we are not aware of one. Some Italian municipalities do provide it: Portoferraio, for example, with a 30% reduction of the variable share.
Choosing, service, experience
- Which model do you recommend?
- It depends on how many people you are, how much you cook and how much quiet matters. Two questions and we point you to the right model.
- If it breaks, who repairs it?
- InSinkErator service in Italy, in and out of warranty, is handled by RiEko, the official distributor: requests are opened through the form on their website, linked from our Service and warranty page. In Milan and its province, home visits are carried out by us on RiEko's behalf.
- As plumbers, do you recommend it? What is the benefit people notice most?
- Yes. It is one of those products you do not miss until you try one: after that, a kitchen without it is hard to imagine. The main benefit is convenience: you deal with leftovers while cooking or tidying up, straight from the sink. Fewer food waste bags, fewer odours, a cleaner cabinet under the sink.
- Does everyone have one in the United States?
- It has been common for decades: according to the American Housing Survey, in 2007 about half of US homes had a disposer. And near Milan too there are people who have used one for half a century: in San Felice di Segrate, back in the early 1970s, homes were already sold with a disposer as standard.
FAQ
Check your area
Pick or type your municipality: we tell you who runs the water service and which plant receives the wastewater. It is not a yes or no on feasibility — that is established at the address, before installing.
These are the 133 municipalities of the Metropolitan City of Milan: Milan is served by MM S.p.A., the other municipalities by Gruppo CAP.
Sources: Gruppo CAP plant data sheets, MM S.p.A. public pages and the Metropolitan City water authority. Data updated on 19 September 2026.
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Last updated 20 October 2026
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