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Stamp on Hot Water Bottle: What Does It Mean? (2022)

Updated: Jan 21, 2023

Ever got confused by all the stamps and symbols on your hot water bottle? We did too, for a while.

One of these stamps is of particular importance, as it has safety implications for you and your loved ones.

The stamp we are referring to is the one shaped like a flower, with dots in the petals. What does this stamp mean? We gathered all the information you need below, welcome to our newest article!

Stamp on your hot water bottle: the daisy wheel

The flower-shaped stamp on your hot water bottle is known as a daisy wheel and refers to the date your hot water bottle was produced. It’s an important element of your hot water bottle as it also serves as an expiry date. The number in the centre of the wheel indicates the year of production, the petals the month of production, and the dots within each petal indicate the week in which your item was produced.

How do you read the hot water bottle daisy wheel?

The daisy wheel consists of one circle in the centre and 12 sections around this circle, each representing a month of the year. It is also often compared to a flower with 12 petals.

As you can see in the picture below, these petals also have dots representing the week of production. For instance, if the petals have 3 dots in them, the hot water bottle was produced on the 3rd week of the month.

To summarize:

  • Number in the centre: year of production

  • Petals: month of production

  • Dots in the petals: week of production

daisy wheel explanation
Hot water bottle produced in the first week of January 2022

daisy wheel red hot water bottle
Hot water bottle produced in the 4th week of November 2006

Why do hot water bottles have expiry dates?

Although very robust, hot water bottles also get damaged over time, even if you take good care of them. Depending on how you use them, store them, and fill them, the material can wear and tear after a few years. Here is an article we wrote on how to store your hot water bottle.

In general, high-quality hot water bottles last between 2 and 5 years, depending on the brand. For example, Fashy hot water bottles, made of rubber, are said to last 5 years according to the manufacturers.

White hot water bottle with instructions
Translation in English: "The year is in the middle, each flower petal corresponds to a month and the dots in the flower petal correspond to the production week. Example: 2019/02/Week 1"

What should I do once my hot water bottle has expired?

Dispose of it

We recommend you dispose of your hot water bottle once it has expired, as further use increases the risks of leaks and bursts. If your item is still in good shape after the expiry date, you can still use it as a cold pack, by freezing your hot water bottle.

Use it as a frozen hot water bottle

Frozen hot water bottles are great companions in the summertime. Indeed, they can help you cool your bed sheets and body instead of air conditioning or fans for instance. They can also be used as ice packs for injuries such as sprung ankles or sore muscles after a tough workout.

Even if the frozen hot water bottle leaks or bursts, you’re unlikely to get injured. So why not give it a second life?

Final thoughts

The daisy wheel is one of the many symbols you will find on your hot water bottle. Next to the BS 1970:2012 stamp, it’s the most important one.

If you haven’t used your hot water bottle in a while, make sure the check its expiry date using the daisy wheel, indicating if it’s still safe for use. If your hot water bottle has expired, dispose of it or use it as a cold pack to prevent leaks, bursts, and resulting burn injuries.

Hot water bottles in bed


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