Can You Put Plastic in the Dishwasher? What's Safe and What's Not

Plastic is everywhere in the kitchen — containers, cups, cutting boards, utensils, and more. But not all plastic is created equal when it comes to the dishwasher. Here's a complete guide to what plastic is dishwasher safe, what isn't, and how to tell the difference.

The Golden Rule: Top Rack Only

Even dishwasher-safe plastic should always go on the top rack. The heating element in most dishwashers is at the bottom, and the intense heat near the bottom rack can warp, melt, or deform plastic items — even those labeled dishwasher safe.

How to Tell If Plastic Is Dishwasher Safe

Look for one of these indicators on the bottom of the item:

• "Dishwasher Safe" label — the most direct confirmation
• Dishwasher symbol — a plate or glass with water droplets or wavy lines
• Recycling number: Plastics #2 (HDPE), #4 (LDPE), and #5 (PP) are generally more heat-resistant and dishwasher safe. Plastics #1, #3, #6, and #7 are more variable — check the label.

Plastic Items That Are Generally Dishwasher Safe (Top Rack)

• BPA-free food storage containers labeled dishwasher safe
• Polypropylene (#5) cups and containers
• Plastic measuring cups and spoons (check label)
• Plastic cutting boards labeled dishwasher safe
• Silicone items (technically not plastic, but often grouped together — fully dishwasher safe)
• Plastic colanders and strainers (check label)

Plastic Items That Should NOT Go in the Dishwasher

• Plastic items without a dishwasher-safe label — when in doubt, hand wash
• Thin, flimsy plastic containers — will warp even on the top rack
• Plastic #6 (polystyrene / styrofoam) — not heat resistant, will deform
• Insulated plastic travel mugs (unless labeled safe) — can damage the vacuum seal
• Plastic items with printed designs or labels — the print fades and washes off
• Old or scratched plastic containers — scratches harbor bacteria and the plastic may be degraded

What About BPA-Free Plastic?

"BPA-free" means the plastic doesn't contain bisphenol A — a chemical of concern. It does NOT automatically mean dishwasher safe. Always check for the dishwasher-safe label separately from the BPA-free label.

Tips for Washing Plastic in the Dishwasher

• Always use the top rack
• Skip the heated dry cycle — use air dry instead to reduce heat exposure
• Don't overcrowd — plastic items need space for water to circulate
• Secure lightweight items between tines so they don't flip and fill with water
• Check for warping after each wash — if a container starts to deform, retire it

Use the Right Detergent

A quality detergent cleans plastic effectively without leaving residue. The Finish Powerball Dishwasher Pods (amzn.to/3RE929j) are pre-measured, plastic-free, and deliver reliable cleaning for mixed loads including plastic. Add Amazon Basics Rinse Aid (amzn.to/4v4Ts5b) to help water sheet off plastic surfaces and improve drying.

Keep Your Dishwasher Clean

Plastic items can leave residue inside the dishwasher over time. Run a monthly cleaning cycle with Affresh Dishwasher Cleaner Tablets (amzn.to/42P5MKQ) to remove buildup, limescale, and odor-causing bacteria from the pump, tub, and hoses.

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