Plastic in your dishwasher: the machine, the pods and the powder

A dishwasher is a hot, wet, high-pressure box that blasts detergent at your dinner plates for two hours. A lot of it is made of plastic. So is a lot of what you put in it, and often what you put in the little detergent door. Here’s what is known about all three, and the much bigger gap of what isn’t.

What a dishwasher is made of

Dishwashers come in two broad types: a plastic tub or a stainless steel tub. That choice doesn’t make a machine plastic-free. Racks, spray arms, filters, detergent dispensers, door seals, cutlery baskets and the hoses behind the kickplate are, in most machines, plastic or rubber.

The best inventory we found comes from Whirlpool itself. For a 2020 University of Michigan life-cycle study that Whirlpool helped fund and co-author, the company handed over the full bill of materials for a stainless-tub KitchenAid machine. Plastics and rubber came to 11 kg, about 24% of its modelled weight. Stainless steel was about 43%. The plastics list ran to more than a dozen types: polypropylene (the biggest, at 4.3 kg), polyethylene, PET, nylon, polystyrene, acetal (POM), EPDM rubber, ABS, polycarbonate, polyurethane and a little PVC. The paper doesn’t say which part is made of what, and because the same list includes cardboard and wood, some of that plastic (such as the 2.2 kg of polyethylene film) may be packaging. Even so, the “premium” steel-tub version is a lot of plastic.

What makers will tell you about any specific part is much patchier. We read their own spec pages for the table below. Tub material is nearly always stated, because steel is a selling point. What the racks are coated with, what the spray arms and filter are made of, and what the door seal is made of mostly aren’t.

The dishwasher sheds microplastics too

For years the assumption was that dishwashers, like washing machines, probably release microplastics. In 2023 a team at the University of Oviedo in Spain measured it. It is the only study of microplastics from a home dishwasher we found, as of November 2026. A 2024 review of microplastic sources in home kitchens found that very few studies have looked at kitchen appliances at all.

The Oviedo team ran a new Beko dishwasher (made, they say, of stainless steel and polypropylene reinforced with 20% talc) empty, and filtered what came out of the drain. After subtracting the microplastics already in the tap water, which were under 10% of the total, the machine itself released:

• about 270 particles per run on a 15-minute pre-wash with unheated water, and about 1,170 on a 164-minute, 70 °C intensive programme;
• particles that were 94–95% polypropylene, the plastic the machine’s parts were made of (the authors list the basket, dispensers, salt-container lid and spray arms among them);
• a giveaway colour. The machine’s plastic parts were grey except for the spray arms, which were purple. Purple particles never showed up in the tap water but made up 11% to 19% of what came out, pointing to the spray arms as one source.

Two more findings matter for the rest of this article. Brand-new, the machine shed 4,000 to 5,000 particles in its first two conditioning runs, then settled down. And adding a detergent tablet to the empty machine on the intensive programme raised what came off its parts by 35% to 54%. The authors suggest the detergent chemically attacks the machine’s polypropylene parts.

What this study doesn’t show

It’s one machine, one brand of detergent for the main tests, three to nine runs per condition, and particles of about 20 µm and up. Only 30% of particles were chemically identified; the rest were extrapolated by colour and shape. Nanoplastics weren’t measured. And it says nothing about health: this is plastic going down the drain, not onto your plates. Sewage plants catch most microplastics (the authors put removal at around 90%), though not all.

Nobody has compared a plastic-tub machine with a stainless one, or tested whether racks, arms and filters from different makers wear differently. So we can’t tell you that one dishwasher sheds less than another. We can tell you that the one machine that was tested shed its own parts, and shed more on long, hot programmes.

Where the plastic is

We read makers’ own product pages, spec sheets and manuals for nine common US and UK dishwashers and wrote down what they say the tub, racks, spray arms and filter are made of. Where a maker doesn’t put it in writing, the table says “not disclosed”. We didn’t guess from photos or retailer listings, and we didn’t test anything. The Whirlpool and KitchenAid rows come from Whirlpool Corporation’s own trade storefront, because its consumer sites blocked our requests. This is what the companies publish, not a lab result and not a ranking. No maker we checked said what its door seal is made of.

Models and materials change between production runs. This reflects makers’ pages as of November 2026; check the current page for your exact model. Every page we used is in the sources at the end.

Dishwasher	Tub	Racks	Spray arms	Filter
Bosch 800 Series SHP78CM5N (US)	Stainless steel	Not disclosed	Not disclosed	Three-part micro, fine and coarse filter, cleaned by hand; material not disclosed
Bosch 300 Series SHE53C85N (US)	Stainless steel	Not disclosed	Not disclosed	Not disclosed
KitchenAid KDTM404KPS (US)	Stainless steel	“Rack Material: Nylon”	5 wash arms; a “Stainless Steel Wash Arm” listed for the lower and second racks; others not disclosed	“True Self-Cleaning Filtration”; material not disclosed
Whirlpool WDF341PAPM (US)	Plastic	“Rack Material: PVC”	2 wash arms; material not disclosed	Removable “micro-fine filter”; material not disclosed
GE GDF450PSRSS (US)	“Gray Plastic” tub and door liner (“Heavy-Duty Plastic Interior”)	Upper rack “PVC”; lower rack not disclosed	2 (middle and lower); material not disclosed	Removable filter with a hard food disposer; material not disclosed
LG LDFC2423V (US)	“NeveRust” stainless steel	“BPA-Free Nylon Coated Racks and Tines”	3; material not disclosed	3-stage filtration; material not disclosed
Samsung DW80CG4021SRAA (US)	“Hybrid” tub with a “stainless interior door”; rest of tub not disclosed	Not disclosed	“3 Point WashSystem”; material not disclosed	Not disclosed
Fisher & Paykel Series 9 DishDrawer DD24DV2T9N (US)	Not disclosed	Not disclosed	One per drawer; material not disclosed	Mesh drain filter and filter plate, cleaned by hand monthly; material not disclosed
Beko DEN59420D (UK)	Not disclosed	Not disclosed	Not disclosed	Not disclosed

A few things the table doesn’t show on its own:

• Stainless tub doesn’t mean stainless inside. Every steel-tub machine here still has racks, arms or filters that are plastic or unnamed. Only KitchenAid names stainless steel wash arms, and not all five of them.
• Rack coatings are a guessing game. Of nine machines, four name a rack material: nylon twice (KitchenAid, LG) and PVC twice (Whirlpool, and GE for its upper rack). Saying PVC is unusually candid. PVC is the plastic phthalates are mostly used to soften; see our phthalates explainer for why that matters. Neither maker says whether its racks contain any.
• “BPA-free” tells you what isn’t there. LG’s racks are “BPA-free nylon coated”, which is a statement about one chemical, not a list of what the coating contains.
• The filter material matters less than how you treat it. No maker here said what the filter is made of. What they do say is how often to clean it (see the last section).

Pods, tablets, powder and gel compared

Most dishwasher detergent comes in one of four forms. Each puts plastic in a different place.

Form	Wrapped in	Usually sold in	What to watch
Pods and wrapped tablets	Polyvinyl alcohol (PVA) film that dissolves in the wash	Plastic tubs or stand-up pouches; some cardboard	The film is a plastic; see below
Unwrapped tablets	Nothing, or a plastic wrapper you peel off	Cardboard boxes or plastic tubs	A peel-off wrapper is plain single-use plastic
Powder	Nothing	Cardboard boxes, sometimes plastic tubs or pouches	You measure the dose yourself
Gel or liquid	Nothing	Plastic bottles	Bottle every few weeks unless you refill

The table is about formats, not brands. Packaging varies by product and country, so check what’s on the shelf in front of you.

The PVA film, briefly

Pods and many tablets are wrapped in PVA, a water-soluble plastic. When researchers in Milan took apart dishwasher-pod film, it was 70% PVA and 30% additives. Americans use an estimated 12 billion dish pods a year, a figure from a Blueland-funded study. Whether that dissolved PVA then fully biodegrades depends on whether the right microbes are present. Industry tests in sewage-plant sludge say it does; independent tests in seawater say it barely does. We’ve covered that fight in full in our explainer on laundry pods and PVA, and the evidence is the same for dish pods.

Microplastics in the detergent itself

The Oviedo team also checked three tablet and pod brands sold in Spain and found 0.75 to 3.02 microplastic particles per gram, or 12 to 52 per wash. That’s tiny next to what the machine shed. A Chinese study across laundry detergents, toilet cleaners and dishwashing detergents found an average of about 565 particles per kilogram, with toilet cleaners the worst. Neither suggests the detergent is the main source.

The polymers inside the detergent

The bigger question isn’t solid bits of plastic in the tablet. It’s the dissolved polymers that are there on purpose.

Machine detergents use polymers to keep loosened grime from settling back onto glasses and to stop limescale. The ingredient lists of the Spanish products in the Oviedo study all included polycarboxylates, the family that includes polyacrylates and acrylic copolymers. A University of York team surveyed 1,353 household products from the websites of Britain’s four biggest supermarkets and found water-soluble polymers in close to 100% of machine dishwashing detergents.

What happens to them next isn’t well known. The York team notes that common polycarboxylates are not readily biodegradable and slow to break down in the environment. Sewage plants remove anywhere from 9% to 98% of them in standard tests, depending on which polymer. The authors’ overall verdict on water-soluble polymers in household products: their environmental risks are “poorly understood”. One disclosure: the study was funded by the UK’s Natural Environment Research Council and by Reckitt, which makes Finish dishwasher tablets, as an industry partner, and Reckitt staff commented on the research and manuscript.

What the law covers

The EU restricted intentionally added plastic microparticles in 2023. For detergents, the rule applies from 17 October 2028. Microbeads used as scrubbers had no transition period. But the rule excludes polymers that dissolve at more than 2 grams per litre, which takes out PVA film and the dissolved polycarboxylates. It targets solid plastic particles, not plastic chemistry.

In the US, the federal microbead ban covers only rinse-off cosmetics such as face scrubs and toothpaste, not detergents. As of November 2026, we found no federal rule on plastic in dishwasher detergent.

The EU Ecolabel goes further than the law. Under its current criteria, a dishwasher detergent must contain no microplastics and no more than 1 gram per wash of organic ingredients that aren’t readily biodegradable, and any PVA film counts as an ingredient. It also caps primary packaging at 2.4 grams per wash, unless that packaging is more than 80% recycled material. Those criteria date from 2017 and were extended to 31 December 2026 while the Commission revises them, so check for new rules from 2027.

What the dishwasher does to your plastic containers

Heat, detergent and water jets wear plastic down, and worn plastic releases more chemicals and particles. We’ve covered the evidence in our microwaving article, under “The dishwasher ages your containers”. The short version: polycarbonate baby bottles washed 51 times leached far more BPA than new ones, and dishwashing raised chemical leaching from reusable bottles.

The Oviedo study adds a number. Six polypropylene lunch boxes released about 14 particles each on the unheated pre-wash and about 166 each on the hot intensive programme. Interestingly, detergent didn’t make the lunch boxes shed more, although it did for the machine.

Dishwasher or hand-washing?

On water and energy, a modern dishwasher used properly beats the way most people actually wash up. On microplastics, nobody knows.

The most detailed US comparison is the Whirlpool-funded Michigan study. Whirlpool employees washed an eight-place-setting load in a test kitchen on Whirlpool’s campus. Washing under a running tap used 22.8 gallons on average; a sink of water used 6.9; the dishwashers used 3.0 to 3.5 gallons on their normal programmes. Over ten years, typical hand-washing came out at 5,620 kg of CO₂-equivalent against 2,090 kg for typical machine use. There’s a twist that rarely makes it into the appliance ads: hand-washing done the recommended way, in a basin with a cold rinse, came out lowest of all, at 1,610 kg. But two of the three volunteers who tried it said they wouldn’t keep it up.

ENERGY STAR, the US government’s efficiency label, says a certified dishwasher uses less than half the energy of hand-washing and saves 8,400 gallons of water a year. The page doesn’t show the assumptions behind that number.

Much of the European research comes from the University of Bonn’s household technology group, led for years by Rainer Stamminger. A 2024 paper co-written by Stamminger and a Henkel employee says studies show machine dishwashing is “clearly superior” on water, energy and time, and that better habits could cut machine electricity use by more than 20%. That paper discloses that Stamminger works on projects funded by companies that make dishwashers and detergents. Industry money doesn’t make the findings wrong, and the physics is not mysterious: a machine recirculates a few litres, while a running tap doesn’t. But the people who measure this most often are paid by the people who sell the machines and tablets.

And microplastics?

Unstudied. The Oviedo team measured a dishwasher. A separate 2026 study measured kitchen sponges, which shed 0.68 to 4.21 grams of microplastic per person per year depending on the type (we cover it in our cleaning article). One counted particles; the other weighed them. You can’t put them side by side, and nobody has compared the two methods directly. Anyone who tells you one is clearly worse is guessing.

What to do, ranked by evidence

1. Scrape, don’t rinse, and run full loads. In the Michigan study, pre-rinsing used 3.5 gallons a load, about as much as the machine. ENERGY STAR says rinsing increases the total water and energy used and that a machine uses about the same whatever the load. This is the best-supported advice here, though it’s about water and energy, not plastic.
2. Use the eco programme. In the Oviedo study, the long, hot programme shed four times as many particles from the machine as the short unheated one, and far more from lunch boxes. Eco programmes are long but run cooler, so we can’t say from that study how they compare. In the EU, every machine has had to offer an eco programme since March 2021, set as the default on machines that pick or remember a programme, and it’s the programme the efficiency ratings are based on.
3. Keep plastic food containers out of hot, heavy programmes, or hand-wash them. The lunch-box numbers above, plus the chemical-leaching evidence in our microwaving article, point the same way. The Oviedo authors recommend glass lunch boxes. Retire plastic tubs that are cloudy, scratched or warped.
4. Choose powder or unwrapped tablets in cardboard. That avoids PVA film, a plastic tub and a single-use wrapper in one go. If you’re in Europe, the EU Ecolabel currently guarantees no microplastics, a cap on non-biodegradable ingredients and less packaging. It doesn’t guarantee polymer-free.
5. Clean the filter. Bosch, for example, recommends cleaning it every few months; your manual will say how often. It keeps the machine draining and cleaning properly. Whether it changes how many microplastics go down the drain hasn’t been studied, but whatever you lift out of the filter can go in the bin rather than the sink.
6. Fix it instead of replacing it. A new machine shed 4,000 to 5,000 particles in its first two runs, and the one bill of materials we have lists 11 kg of plastics and rubber. In the EU, makers must sell racks, baskets, spray arms, filters and seals to the public for at least 10 years after a model is discontinued. A cracked rack or worn arm is a part, not a new dishwasher.
7. If you’re buying anyway, a stainless tub replaces one large plastic surface with steel. But racks, arms and filters are still plastic in most machines, and no study shows a stainless-tub machine sheds less. Ask the maker what the racks and spray arms are made of; the table above shows how rarely they say.

Where the evidence is weak: everything about dishwasher microplastics rests on one Spanish machine. Detergent polymers are barely studied once they leave your kitchen. The water and energy comparisons are solid on the physics but mostly funded by industry. We don’t currently vet dishwashers or detergents against our standard, so we’re not naming any as better than others.