There is a problem identifying the right stopper as all stoppers look the same so it’s easy to assume they all fit the same. Best to think of it like car tyres, they all look the same but you couldn’t put a Focus tyre on a motorbike. Each manufacturer makes to a specific and exact size, the replacement must match to create a lasting watertight seal.  It’s the lasting seal that is important as you can buy a stopper that is a near fit, and it will plug the hole.  But after time and use that near fit will wear and force uneven thread causing either a crack to the neck or broken seal which will inevitably lead to a leaking bottle.

Years ago when only a few manufactures produced locally it was easier to buy the rubber seal and replace just that part.  With improved production technics and new patents these simple rubber seals have become more sophisticated.  Most are now an integral part of the stopper, it’s not just a plug to stop water but a solid and sturdy custom stopper.  These improvements have evolved over the years to offer the best and most secure hot water bottles ever made.  Each manufacture will have their own moulds, designs and often patents that are protected.  Getting a replacement part is not so easy, it must be like for like. 

Things have moved on since the old stoppers, Fashy manufacture a much wider stopper and it is rubber free, no latex seal.  They are amazing and work beautifully well, last for years and it’s specific to Fashy.  Other manufactures have tried to copy and there are some now without a rubber seal, these are new, and time will tell if these are as good as Fashy.  The traditional stopper with a rubber seal is still available on good traditional rubber bottles and will continue for those that prefer them.

To replace first look for a maker’s mark, these are embossed into the rubber usually at the base of the bottle.  However, there are a lot of generic products in the shops and supermarkets that only put shop name on the packaging.  Once out of the bag it can be difficult to tell where it was purchased from, some might say this is deliberate as should it leak there is no trace to the shop or supermarket.  Also, some traders import hot water bottles without any certification, they really don’t want anyone to know where it came from and avoid branding at all costs.  If you have a generic product there is no easy way to get a replacement stopper, these types are the most dangerous and most difficult to resolve.

When replacing a stopper its worth having a good look at the bottle and its age.  Stoppers will last the life of the hot water bottle.  If the stopper is worn or the rubber has perished there is very good chance the same has happened to the bottle.  Take a few minutes to inspect, first look at the general condition, look for wear patterns, creases, cracks and feel if the bottle is thin in areas especially around the belly.  Hot water bottles wear out from the inside out, rubber is a natural ingredient and will over time perish.  Average age is 3 years, if you have owned it for over 3 years and the stopper has failed the bottle will not be long after.  It’s not worth taking a risk on something that has to carry hot water and may be used in a bed, next skin and could fail at any time.  Invest in a decent well-made product that has a British Standard mark BS1970 or branded ones which carry CE and now EU approved TÜV independent testing for the highest quality.

If you have just lost a stopper there is help, reputable suppliers will hold stocks of spare stoppers and be able to supply. 

So always buy a genuine replacement stopper for high quality brands such as Fashy, Sänger, Hugo Frosch & Coronation. Best advice is to first buy a good quality branded hot water bottle and look after it, chances are you will never need to replace the stopper.