Putting plastic through the dishwasher
Major impactHeat plus alkaline detergent plus high-pressure jets, repeatedly.
The short answer
A dishwasher is a fairly hostile environment: water above 60°C, strongly alkaline detergent and abrasive jets, applied for an hour, hundreds of times over a container’s life. It is the main reason reusable plastic goes cloudy — and cloudiness is visible evidence that the surface has degraded and is shedding.
Why it happens
- Wash temperatures well above ambient accelerate surface degradation
- Alkaline detergents chemically attack some polymers, notably polycarbonate
- Jet impingement is direct mechanical abrasion
- Effects accumulate over hundreds of cycles
The fix, easiest first
- Hand wash plastic in cool water with a soft cloth
- If it must go in, use the top rack and the coolest cycle
- Retire anything cloudy, rough to the touch or smelling of old food
- Move to glass and steel, which are genuinely dishwasher-indifferent
Packaging this applies to
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Get my exposure scoreFrequently Asked Questions
Is it bad to put plastic in the dishwasher?
A dishwasher is a fairly hostile environment: water above 60°C, strongly alkaline detergent and abrasive jets, applied for an hour, hundreds of times over a container’s life. It is the main reason reusable plastic goes cloudy — and cloudiness is visible evidence that the surface has degraded and is shedding.
Why does this happen?
Wash temperatures well above ambient accelerate surface degradation. Alkaline detergents chemically attack some polymers, notably polycarbonate. Jet impingement is direct mechanical abrasion. Effects accumulate over hundreds of cycles.
What should I do instead?
Hand wash plastic in cool water with a soft cloth. If it must go in, use the top rack and the coolest cycle. Retire anything cloudy, rough to the touch or smelling of old food. Move to glass and steel, which are genuinely dishwasher-indifferent.
Sources
- Earth Action with rePurpose Global (2026). Microplastic migration from food and beverage packaging (reported May 2026). Forbes.
- Qian N, Gao X, Lang X, et al. (2024). Rapid single-particle chemical imaging of nanoplastics by SRS microscopy. Proceedings of the National Academy of Sciences (PNAS).
- Winkler A, Santo N, Ortenzi MA, et al. (2022). Does mechanical stress cause microplastic release from plastic water bottles?. Water Research.
- Hernandez LM, Xu EG, Larsson HCE, et al. (2019). Plastic teabags release billions of microparticles and nanoparticles into tea. Environmental Science & Technology.