Hot water bottles have an expiry date - here's the hidden way to check yours

People are just finding out that hot water bottles have an expiry date and if the rubber perishes they could be in real danger

hot water bottles have an expiry date
(Image credit: Getty Images)

People are just now discovering that hot water bottles have an expiry date and can be quite dangerous if the rubber is old.

During the winter months, many of us rely on hot water bottles and electric blankets in order to keep warm at night. While hot water bottles are safe when used properly, they do have expiration dates that need to be closely followed. But how can you check that your hot water bottle is in date? Here is everything you need to know.

hot water bottle

(Image credit: Getty Images)

How to check your hot water bottles expiry date

People have discovered the meaning behind the flower symbol on their hot water bottles. The symbol indicates the expiration date of the hot water bottle and how long you should wait until you throw your bottle out.

On every hot water bottle, there should be a circular flower shape with twelve petals. The number in the center of the flower shape indicates the year that it was made ie: 20 means 2020, 19, means 2019, etc. 

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The petals also show the month that the hot water bottle was made. The four bumps show each week of the month, so users can see exactly when their bottle was made. For example, just four bumps on the first petal would indicate that the bottle was made on the fourth week of January. Two bumps on the tenth petal on the flower would suggest that the bottle was made on the second week of October.

On TikTok some users have shared their finding and explained to others how they can check their own bottles. 

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How long do hot water bottles last?

Typically hot water bottles last around three years before the rubber perishes. Some bottles may last longer or shorter depending on the thickness of the rubber and the quality of the product and some doctors recommend using a hot water bottle for just two years before replacing it.

The best idea is to check your specific hot water bottle's expiration date and make a note to throw it away once that date is reached. 

hot water bottle

(Image credit: Getty Images)

What are the dangers of using an expired hot water bottle?

As the water inside a hot water bottle is boiling, the major concern to users' health is burning their skin. Speaking to woman&home, Dr. Deborah Lee from Dr Fox Pharmacy (opens in new tab) explained the dangers of using an expired hot water bottle. 

"It's imperative people do all they can to avoid burns and scalds from hot water bottles. Hot water on the skin can cause first, second and third-degree burns.  The skin of the groin and legs is often affected. These injuries are very painful, can blister, and may need hospital admission," said Dr. Lee. 

The expert added that burns can also lead to infection and other serious issues. "Burns are at high risk of secondary infection and can cause sepsis, which is life-threatening. They can result in nerve and muscle damage, affecting the ability to walk. Severe burns may require skin grafting," she said. 

Dr. Lee even warned that prolonged exposure can lead to skin cancer in extreme cases. "Prolonged use of a hot water bottle on the skin can cause a rash known as erythema ab igne – characterized by redness, hyperpigmentation, and scarring at the site of the heat. Excessive heat directly on the skin has harmful consequences. In the long term, this can increase the risk of skin cancer," she said.

Laura Harman

Laura is a news writer for woman&home who primarily covers entertainment and celebrity news. Laura dabbles in lifestyle, royal, beauty, and fashion news, and loves to cover anything and everything to do with television and film. She is also passionate about feminism and equality and loves writing about gender issues and feminist literature.


Laura loves drinking and eating and can often be found trying to get reservations at London's trendiest restaurants. When she's not wining and dining, Laura can also be found travelling, baking, and hiking with her dog.