10 Things You Shouldn’t Put on the Bottom Rack of Dishwasher
10 Household Items You Should Never Place on Your Dishwasher's Bottom Rack
Plastic food containers not clearly dishwasher-safe
Insulated travel mugs and tumblers
Wooden utensils and cutting boards
Fine glassware and crystal
Nonstick pans and bakeware
Sharp knives
Lightweight plastic lids
Plastic measuring cups and spoons
Decorative or hand-painted dishes
Baby bottles and baby accessories
-
1 / 10
At first glance, the bottom rack of a dishwasher seems like the most powerful spot. It’s closer to the heating element, receives stronger water pressure, and is designed to handle heavy-duty cleaning. That’s exactly why many people assume everything can safely go there. In reality, the bottom rack is also the most dangerous place for many household items.
High heat, intense spray, and direct exposure to the heating element can warp, crack, fade, or completely ruin certain dishes and tools—sometimes after just one wash. If you’ve ever pulled out a melted container, cloudy glass, or damaged utensil and wondered what went wrong, the bottom rack is often the culprit.
Here are 10 things you should never put on the bottom rack of a dishwasher, and where they should go instead.
1. Plastic Containers (Unless Clearly Marked Dishwasher-Safe)
Thin plastic food containers are extremely vulnerable to heat.
The bottom rack is closest to the heating element, which can cause plastic to warp, melt, or release harmful chemicals—especially if the plastic isn’t explicitly labeled as dishwasher-safe.
What happens:
Warping and deformation
Melting edges
Potential chemical leaching
Better option:
Place plastics on the top rack only, where temperatures are lower and water pressure is gentler.
2. Insulated Travel Mugs and Tumblers
Many insulated cups and tumblers rely on a vacuum seal to keep drinks hot or cold. High heat from the bottom rack can break this seal permanently.
What happens:
Loss of insulation
Water trapped between layers
Shortened lifespan
Even if the mug claims to be dishwasher-safe, that usually applies to the top rack only.
Better option:
Hand-wash or place on the top rack if the manufacturer allows it.
3. Wooden Utensils and Cutting Boards
Wood and dishwashers are a terrible combination—especially on the bottom rack.
The intense heat and prolonged moisture exposure cause wood to swell, crack, split, or lose its natural oils.
What happens:
Cracking and splintering
Warping
Bacterial growth in damaged wood
Better option:
Always hand-wash wooden items and let them air-dry completely.
4. Fine Glassware and Crystal
Delicate glasses may survive a few cycles, but the bottom rack puts them at high risk.
Stronger water jets can knock them over, while high heat can cause cloudiness or micro-cracks that weaken the glass over time.
What happens:
Chipping and breakage
Permanent cloudiness
Reduced clarity
Better option:
Use the top rack or wash by hand if the glassware is especially valuable.
5. Nonstick Pans and Bakeware
Many nonstick items are labeled dishwasher-safe, but that doesn’t mean the bottom rack is a good idea.
High heat can degrade the nonstick coating, reducing its effectiveness and lifespan.
What happens:
Peeling or flaking coating
Loss of nonstick performance
Potential chemical exposure
Better option:
Hand-wash gently or place on the top rack only if the manufacturer approves.
6. Sharp Knives
Putting knives on the bottom rack is bad for both the knife and you.
The intense water pressure and heat can dull blades quickly, while loading and unloading becomes a serious safety hazard.
What happens:
Dull blades
Increased rust risk
Higher chance of cuts
Better option:
Wash knives by hand and dry immediately to maintain sharpness and safety.
7. Lightweight Plastic Lids
Even if the matching container survives, plastic lids often don’t.
They’re thin, flexible, and prone to flying around during the wash cycle, where they can land on the heating element.
What happens:
Warping and melting
Misshapen lids that no longer seal
Clogged dishwasher parts
Better option:
Secure lids on the top rack, ideally clipped in place.
8. Measuring Cups and Measuring Spoons (Plastic)
Plastic measuring tools may look sturdy, but the bottom rack can slowly ruin their accuracy.
Heat can warp them just enough to throw off precise measurements—something you may not notice until recipes start failing.
What happens:
Warping
Inaccurate measurements
Faded measurement markings
Better option:
Top rack only, or switch to metal measuring tools for durability.
9. Decorative or Hand-Painted Dishes
Decorative plates, bowls, or mugs often have glazes, decals, or hand-painted designs that aren’t meant for extreme heat.
The bottom rack’s temperature and pressure can cause fading, cracking, or peeling.
What happens:
Faded designs
Cracked glaze
Permanent damage
Better option:
Hand-wash or use the top rack on a gentle cycle if permitted.
10. Baby Bottles and Baby Accessories
Baby items deserve extra care, and the bottom rack is too harsh for many of them.
High heat can weaken plastic, distort shapes, and reduce the lifespan of nipples, valves, and seals.
What happens:
Warping
Reduced effectiveness
Safety concerns
Better option:
Use the top rack or a dishwasher basket designed specifically for baby items.