Can You Microwave Plastic Water Bottle? (Solved)

Categorized as Microwave Safety
Can You Microwave Plastic Water Bottle

Microwaving a plastic water bottle may seem like an easy way to quickly heat up your drink, but is that actually safe? Find out the risks and benefits of microwaving a plastic water bottle.

We’ll go over what would happen if you microwave it, how much time it takes to heat up in a microwave, as well as the science behind it.

Can You Microwave Plastic Water Bottle?

In general, you can’t microwave a plastic water bottle unless the water bottle has been specifically designed for use in a microwave. This bottle is marked with a “microwave-safe” label approved by the FDA.

Here’s a short guide on how to microwave “microwave-safe” plastic water bottles:

Put the plastic water bottle into the microwave. Remove the cap on the water bottle, if there is one. Turn the microwave to the lowest setting. Microwave the water bottle for 20 seconds.

Why You Shouldn’t Microwave Plastic Water Bottles

There are some risks and benefits associated with microwaving a plastic water bottle. The risks can range from melting to leaching chemicals into your drink, which is why it is not recommended that you microwave these types of bottles.

However, there are microwaveable plastics that have been tested for safety when put in a microwave. If you do own one of these microwavable water bottles, then the answer is yes, microwaving your plastic bottle is safe!

You can differentiate between microwavable plastics and the regular kind by looking for a microwave-safe label. The symbol usually looks like the shape of the microwave with three squiggly lines inside of it. It can generally be found on the bottom of the container.

In the US, the FDA is an agency that controls and regulates the safety of different materials. And for one water bottle to be awarded the label of “microwave safe,” it will have to go through a very stringent testing process.

If a plastic bottle has passed the FDA standards, then you can be sure that it is safe to put inside of a microwave as the number of chemicals leaching into your food or drink will be negligible.

Can You Microwave a Plastic Water Bottle Safely Even If It Doesn’t Have a “Microwave-Safe” Label?

Even if a plastic water bottle does not have the “microwave-safe” label, it doesn’t necessarily mean it is unsafe for use in a microwave. It just means that the bottle has not specifically been tested for such use by the FDA.

Due to the sheer number of plastic bottles on the market, it would be a daunting task for the FDA to test every single one of them. Therefore, in most cases, it’s up to the manufacturer to seek this test out.

Heating a container without a microwave-safe label in the microwave is still possible. The risk involved, however, is that hormone-like chemicals may leak into your drink or food while exposed to high heat, such as when in a microwave.

Two of the most concerning chemicals would be BPA and phthalates, both of which have been shown to disrupt the endocrine system and linked to various health conditions such as cancer.

Furthermore, according to some studies, many plastics marked as “BPA free” may not be as safe as advertised. Thus, even though the manufacturers have attempted to substitute the BPA chemical with something else, they may have merely swapped one bad ingredient for another.

There is growing evidence that these BPA-free alternatives may have harmful effects on the body as well. In mice, they decreased sperm quality and lessened fertility. Though these results had been mainly limited to mice, the researchers believed the results would be the same, if not similar, for humans as well.

So, in my opinion, if you own a plastic water bottle with or without a “microwave-safe” label, it’s best not to put it in your microwave.

Different Types of Water Bottles and Their Microwave Safety

Before you put any type of plastic material into your microwave, it’s good to know that not all plastics are created equal.

Some types of plastics can withstand high heat and repeated exposure, while others cannot. Additionally, some types of plastics may contain harmful chemicals that could leach into your food or drink when exposed to high heat, like microwaves.

There are seven different types of plastic materials, each with its own set of unique properties. Each type of plastic has a number assigned to it, such as #1 or #2. The number is there to identify what kind of plastic the item is made from and the manufacturing process used in making it.

In terms of microwave safety, plastic number 5 is the safest type made from polypropylene. They are commonly used to make everything related to food and beverages, such as food containers, baby bottles, and water bottles. Once again, please remember that microwave-safe only means that the heated plastic will not be deformed when exposed to microwaves, but it does not mean that they are free from chemicals.

Some studies suggest that even microwaveable plastics can leak harmful chemicals that cause asthma and hormone disruption so it is best to play it safe by substituting with glass dishes.

How Do You Microwave a Plastic Water Bottle: Step-By-Step

If you intend to microwave a plastic water bottle, make sure to find out first what type of material it is made from. The best bet would be to look for a #5 plastic containers as they are the safest option.

After you have identified the best type for microwaving, follow these steps.

1. Set Your Microwave’s Power to Low

Even if the water plastic bottle is made from a safe, microwave-safe plastic material, they are still more likely to melt if the microwaves are too powerful. So the first thing you want to do is set your microwave to the lowest possible power. That way, there will be less risk of deforming or melting the plastic during the heating process.

2. Remove the Bottle Lid

Microwaving a plastic water bottle with the lid on will cause a build-up in pressure inside. This, in turn, may result in a possible explosion of the container itself. You don’t want that to happen so take off the lid before exposing your plastic bottle to microwaves.

3. Microwave in Short Increments Until the Water Is Warmed

The safest way to microwave a plastic water bottle is by microwaving it in increments of time. It is best to start at 15 seconds and check the material’s progress after each interval. If no deformation occurred, it means you can increase the next increment by 10 seconds. Continue this process until the water inside the bottle is warmed.

How Long Can You Microwave a Plastic Water Bottle?

The exact time you should microwave a plastic water bottle will vary based on the temperature of your microwave, the type of plastic material in use, and the amount of liquid inside the bottle.

That being said, in general, you can microwave a microwave-safe plastic water bottle with liquid inside for up to 5 minutes on low heat. Anything above 5 minutes may cause the plastic to melt and potentially leak chemicals into your food or drink.

Safety Tips to Microwave Plastic Water Bottles

Here are some additional tips you can use to ensure that your plastic water bottle doesn’t melt or leak chemicals when microwaving:

  • Only use microwave-safe plastic bottles.
  • Don’t overheat the water bottle by microwaving it for more than 5 minutes at a time.
  • Don’t microwave an empty water bottle because there is nothing in it to absorb the heat and spread evenly throughout the container.
  • Microwave in short increments for a few seconds at a time. This will help distribute the heat more evenly and avoid warping or melting the container.
  • Always check the plastic bottles to ensure that they are in good condition before putting them in the microwave. Look for any cracks or holes.
  • If you need to microwave your water bottle frequently, use an alternative container such as microwave-safe glass.
  • To be on the safe side, always use your own judgment when microwaving any type of plastic material. If it doesn’t feel right, then don’t do it!


So can you microwave a plastic water bottle? The answer is yes, but only if you use a plastic water bottle with a microwave-safe label on it and only if you follow the safety precautions outlined in this article.

For your safety and peace of mind, I suggest that you transfer your liquid to a microwave-safe glass container before microwaving.

That way, you will be able to avoid the risk of spilling while heating and any chemicals that may leach into your food or drink if the plastic material melts.

If you’re looking for information on microwaving other types of bottles, including Nalgene water bottles and plastic baby bottles, be sure to check out our other posts!

By Rosie Elliott

I’m Rosie. I’m a professional chef with experience in Western, Mediterranean, and Italian cuisine. I’ve been cooking for over 15 years, and I have two daughters that keep me busy!