Dishwashers are a modern convenience that save time and effort when cleaning pots and pans, cutlery, and a variety of items in your home. However, you may have come across the term “dishwasher safe” without fully understanding what it implies. In simple terms, when an item is dishwasher safe, it means the manufacturer has verified that the object can endure the high temperatures and chemical process of being washed in a dishwasher without incurring damage.
This guide explains exactly what dishwasher safe means, which materials can typically be put in the dishwasher, and how to identify dishwasher safe symbols to protect your belongings. We’ll also explore what happens if you dishwash something that isn’t dishwasher safe, and answer frequently asked questions about the dishwasher safe icon and commonly used materials like plastic items, ceramics, and glass.
Understanding “Dishwasher Safe”
When an object is marked “dishwasher safe,” it has been tested to withstand the mechanical action of dishwasher cycles, exposure to dishwasher detergents, and the heat used to dry dishes. Typically, these items have:
- Suitable Materials and Coatings: The type of glaze used in dishwasher safe ceramics, or the protective layers on metals, are designed to endure repeated washing.
- High Melting Point (for Plastics): Dishwasher safe plastics are composed of materials with a higher melting point, so they won’t warp or lose shape.
- Proper Sealing: Some items—like double-walled cups—must have adequate sealing to prevent water infiltration during the wash.
It’s worth noting that “dishwasher safe” can still have qualifiers. For instance, some manufacturers specify placing an item on the top rack of the dishwasher only, because that section is often slightly cooler and gentler than the lower rack. So, always read labels carefully to avoid damage.
What Is Considered Dishwasher Safe?
Common Dishwasher Safe Items
- Plates, Bowls, and Mugs: Many everyday dishes—particularly those with glazes formulated for higher heat—are safe for the dishwasher.
- Stainless Steel Cutlery: High-quality stainless steel resists corrosion and typically fares well in a dishwasher.
- Stainless Steel Pots and Pans: In most cases, stainless steel cookware can handle dishwasher temperatures without rusting, although you should avoid harsh detergents that could dull the surface.
- Dishwasher Safe Plastics: These are plastics with a high melting point (like polypropylene) that can withstand the heat of dishwashing.
- Glass and Crystal: Sturdy dishwasher safe glass is typically safe, but delicate crystal may not always do well due to potential etching over time.
Labels and Icons
To ensure you’re not guessing whether something can be put in the dishwasher, look for the “dishwasher safe” symbol on the item’s base or packaging. This symbol can vary, but generally shows an image of plates or glasses with water droplets or diagonal lines above them—sometimes accompanied by text stating “Dishwasher Safe.” For plastics, the marking may appear as a rectangle (representing the dishwasher) with dishes or lines inside. We’ll delve deeper into the symbol for dishwasher safe on plastic later in this article.
What Happens if You Dishwash Something That Isn’t Dishwasher Safe?
Accidentally putting a non–dishwasher safe item into the dishwasher can result in:
- Warping and Damage: Low-quality plastic items or plastics with a low melting point could distort or completely melt under high temperatures.
- Peeling or Fading: Painted or printed decorations on dishes and mugs could peel, fade, or wash away during the chemical process of the wash.
- Rust or Corrosion: Certain metals (e.g., cast iron, copper, or non-coated steel) can rust, tarnish, or corrode when exposed to dishwasher detergents.
- Glaze Erosion: If a poor-quality type of glaze is applied to ceramics, the high heat and harsh detergents can crack or pit the surface, leading to potential contamination or a ruined finish.
Moreover, you risk damaging other items in the dishwasher if an unsuitable object breaks, chips, or leaches substances into the wash water. Always check labels and err on the side of caution if you’re unsure.
The Symbol for Dishwasher Safe on Plastic
When searching for the symbol for dishwasher safe on plastic, you’ll often see a rectangle featuring either:
- A series of diagonal lines representing water or heat.
- A plate or utensils inside that rectangle.
- Sometimes the text “Dishwasher Safe” is also included.
Alternatively, manufacturers might use a simplified icon with a plate, glass, or utensils accompanied by small water droplets. Keep in mind that many plastic items also list a recommended rack of the dishwasher (e.g., top rack only) because the heating element is typically located near the bottom of most dishwashers, creating higher heat in that area.
Tip: Avoid using the dishwasher for plastic items that don’t specify “dishwasher safe,” especially if you notice no label. Items such as disposable or single-use plastic containers are likely to melt or warp easily.
What Items Cannot Be Put in the Dishwasher?
Some items generally should not be exposed to the extreme temperatures and detergent conditions of a dishwasher. These include:
- Cast Iron Cookware: Cast iron pans require specific care, and the seasoning layer can be ruined by a dishwasher’s harsh environment.
- Wooden Utensils or Cutting Boards: Wood can swell, warp, or crack due to prolonged exposure to water and heat.
- Copper and Certain Aluminium Cookware: Copper develops a unique patina over time, which can be stripped away or discoloured by dishwasher detergents. Aluminium cookware may also discolour or pit.
- Fine China, Hand-Painted Ceramics, or Antique Porcelain: The type of glaze or delicate pattern may not withstand the intensity of dishwasher cycles.
- Insulated Mugs or Bottles: If not specifically labelled dishwasher safe, water can get trapped between layers, diminishing insulation properties.
When in doubt, a quick rinse by hand can preserve delicate items and maintain their longevity.
Dishwasher Safe Glass, Ceramics, and More
- Glass: Most modern glassware is designed to tolerate the temperature fluctuations of dishwashers. However, thin or older glass (including some decorative items) might crack under extreme heat, so check labels.
- Ceramics: Dishwasher safe ceramics usually have a robust glaze. However, if the manufacturer notes a specific cleaning method, or if the glaze is easily scratched or chipped, it’s best to hand-wash.
- Stoneware: While many stoneware dishes are marketed as dishwasher safe, older or artisanal pieces might not have been fired or glazed to modern standards.
If you’re unsure whether the glaze is applied in a way that meets modern dishwasher standards, opt for a gentle hand-wash until you’re certain it can stand up to the temperature and detergents.
Caring for Dishwasher Safe Items
Ensuring your dishwasher safe items last includes a few best practices:
- Pre-Rinse or Soak Tough Residue: While modern dishwashers and detergents can handle a lot of grime, scraping off excess food residue helps maintain cleanliness and reduces the likelihood of staining or scratching.
- Use the Recommended Detergent: Harsh detergents can dull finishes over time. Consider a gentler, eco-friendly option to preserve both your dishes and the environment.
- Avoid Overloading: Stacking dishes too closely can prevent water and detergent from reaching all surfaces, leaving residue behind. It may also cause chipping or scratching if dishes knock into each other.
- Place Plastics on the Top Rack: Plastic items with “top rack only” instructions should never sit near the bottom, where they might melt or warp.
Final Thoughts
Understanding what “dishwasher safe” means is about more than just convenience—it’s about ensuring your treasured dishes, cookware, and utensils remain in top condition. By checking dishwasher safe icons, paying attention to the symbol for dishwasher safe on plastic, and knowing what items cannot be put in the dishwasher, you’ll protect your belongings and maintain a smooth dishwashing routine.
For an even greener, more convenient approach to dish care, why not consider switching to an eco-friendly detergent option? Explore our Dishwashing Detergent Sheets for a powerful, residue-free clean that’s kind to both your dishes and the planet. Whether you’re washing pots and pans or your favourite ceramic mugs, these sheets dissolve quickly, tackle stubborn grease, and are perfectly suited to modern dishwasher technology.
By taking the time to choose the right cleaning method—and the right products—you’ll keep your kitchenware pristine, your appliances running efficiently, and your carbon footprint lower. That’s a win for everyone—happy dishwashing!
