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  • Writer's pictureCancerPal

Is your hot water bottle safe to use?

Hot Water Bottle image

Heat therapy is an effective way of relieving cancer related aches and pains, and as most of us have a hot water bottle lying around at the bottom of a drawer or cupboard somewhere, using a hot water bottle can be one of the most convenient ways of using heat for pain relief.

But, did you know that hot water bottles have a shelf life? Before you reach for your trusty, old hot water bottle, please take a moment to check that your hot water bottle is still safe to use.


Safety standards for hot water bottles

British Standard BS1970:2012 is an internationally recognised UK safety standard for rubber and PVC hot water bottles, that provides minimum specifications for hot water bottles to help ensure consumer safety. The safety standards are mainly associated with filling instructions and general safety, but also include certain manufacturing best practices.

Example of the British Safety Standard BS1970:20212 embossed on the neck of a hot water bottle
British Safety Standard Number

It's important to check that any hot water bottle you own or purchase conforms to this safety standard. The safety standard should be permanently marked on the hot water bottle and is usually stamped on the bottle neck along with the manufacturer’s and/or distributors mark so that in the event of a serious defect the manufacturer/distributor can be located.

Replace a hot water bottle every 2 to 3 years

The recommended shelf life of a hot water bottle isn't actually outlined within the British Standard BS1970:2012, but the general recommendation seems to advise replacing your hot water bottle every two to three years. Most hot water bottles are made from rubber or polyvinyl chloride (PVC) and these materials degrade over time and with usage, meaning that older hot water bottles may burst or leak and could cause serious burns.

How can I tell how old my hot water bottle is?

Every hot water bottle sold in the UK should have a 'date daisy' imprinted on the neck of the hot water bottle, which shows the date that it was manufactured.

Example of the date daisy embossed on a hot water bottle

The number in the centre of the wheel shows you what year it was made, so in the image to the right it says 22, meaning it was made in 2022.

There are also 12 segments around the centre of the wheel. Usually, the number of these segments that have dots in show you in which month the hot water bottle was made. So, if the image to the right, there are dots in eight sections, meaning the hot water bottle was made in August.

The number of dots in the final (or only) filled section shows in which week of that month the hot water bottle was made. So, in the image above, four dots means the fourth week of the month.

Date of manufacturer vs date of first use?

Whilst the date daisy can help us to establish whether the hot water bottle at the back of the cupboard is still safe to use, what happens if we purchase a brand new hot water bottle that was manufactured 6 months ago? Has the shelf life of the hot water bottle already decreased by 6 months?

Just as there is no formal guidance around the shelf life of a hot water bottle, there is also no formal guidance around whether you should replace your hot water bottle from the date of manufacturer or the date of first use. So we decided to undertake a bit of research into whether rubber degrades with age or with use.

According to data we found in the Military Standardisation Handbook for Rubber Products, the recommended shelf life of natural rubber (not specifically hot water bottles) is 3-5 years. The Military Standardisation Handbook for Rubber Products defines shelf life as the recommended amount of time that a rubber material can be kept in storage.

It's also worth considering that there are different price points and grades of all sorts of household commodities, including hot water bottles. Higher quality items are better designed, finished and tend to be manufactured using higher grade components to last longer and so cost more than budget items. A budget hot water bottle is often manufactured to hit a price point and they are not necessarily made to last. A budget hot water bottle may therefore need replacing sooner than a higher quality hot water bottle.

Whilst we're certainly not experts in rubber or in hot water bottle shelf life, we hope the information above can help you make up your own mind about whether it's time to purchase a replacement hot water bottle.

Additional hot water bottle safety checks?

In addition to checking that your hot water bottle meets the British Safety Standards and hasn't reached the end of its usable life, you should check your hot water bottle for visible signs of wear or damage before each use and don't use a hot water bottle that is cracked, worn or leaking.

It's also a good idea to fill a new hot water bottle with cold water before its first use to ensure the bottle is in perfect condition and fills properly. Gently squeeze the hot water bottle (over your sink!) to check it doesn't leak.

How to store a hot water bottle?

Rubber is a natural substance that will perish over time. The correct storage of a hot water bottle can maintain its functionality and extend its lifespan. It keeps the material from getting damaged and prevents the growth of mould and bacteria that can affect your health.

A hot water bottle that has been stored badly i.e. in damp, humid, wet or hot conditions, or exposed to intense sunlight is likely to degrade. A hot water bottle in poor condition could have weak spots that may prove dangerous if filled with hot water.  

So how do you correctly store a hot water bottle?

  1. After each use, it is important to empty the hot water bottle and if possible hang it upside down to dry. Storing a wet hot water bottle can cause mould to grow inside the bottle.

  2. Once the inside of the hot water bottle is completely dry, store it in a cool, dry and dark location with the stopper removed. Exposure to excess sunlight can cause oxidation and removing the stopper will prevent any humidity and rot from building up inside your hot water bottle.

  3. You should avoid contact with hot surfaces, household chemicals, oil or grease as this can damage your hot water bottle material.

  4. Keep away from sharp objects to avoid punctures and do not place heavy objects on top of the bottle to prevent damage or deformation.

Looking after your hot water bottle every time you use it will help it last longer and ensure that you can safely enjoy the therapeutic heat benefits that the trusty hot water bottle has to offer. 


CancerPal sells a range of heat therapy products in the Pain Relief section of the CancerPal MarketPlace.

All hot water bottles sold on CancerPal meet the BS1970:2012 British safety standard applicable to hot water bottles, so you can buy with complete confidence. 


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