Bottled water tamper evident seals; a false sense of security?
When it comes to the subject of avoiding travellers’ diarrhoea, some of the advice given to those heading overseas appears to be ubiquitous.
• “Drink bottled water from a reliable source, but check the seal is intact before you drink.” 
• “non-carbonated bottled water with intact seals can generally be assumed to be safe to drink” 
• “Bottled water is the safer choice for drinking water. The seal must not have been tampered with.”
• “Drink bottled water that is sealed” 
This type of advisory from government health authorities is routinely repeated on the websites of state and private travel health providers, and is given out by medical practitioners in pre-travel consultations.
However, the reality of ‘fake’ or counterfeit bottled water production means that such advice may require additional qualification if it is not to become a cause of complacency and create a false sense of security.
At the lower end of the ‘fake’ water scam scale, discarded single-use plastic water bottles are simply collected, re-filled, and re-capped before being offered to unsuspecting purchasers by street vendors. They may even find their way to you as a ‘complimentary’ gift from your hotel.
Even when the bottle itself appears to be in fairly good or new condition, these fakes can be relatively easy to spot; when the cap is removed too easily, and there is no corresponding ‘click’ as the cap’s seal is broken, it’s a fairly safe bet that you’re about to drink water that may be far from fit for human consumption.
Refilling the bottles of recognised premium brands may improve an unscrupulous vendor’s ease of passing off ‘fake’ water (and increase the profit margin), as the purchaser’s guard may be lowered by familiarity with recognised branding, but, once again, a disengaged tamper evident cap seal is still a clear signal that all is not well.
The real problem arises when the ease of replacing a sealed cap is recognised.
In more affluent societies instructions for replacing bottled water with alcohol (to avoid access restrictions to such as public events or cruise ship voyages), and then re-sealing the bottle with the original cap, are easy to find online. When it comes to resealing a used bottle with a new cap for the purpose of passing off unsafe water as the original contents, it’s even easier.
Off-the-shelf replacement plastic caps, complete with a new, connected skirt, are inexpensive, readily available in a multitude of colours and sizes, and are simple to fit to previously-used plastic bottles once they have been refilled. For the victim of the scam they provide the reassuring click on removal of the cap, but no protection against a range of waterborne diseases.
Similarly, there is little technical restriction on replacing the shrink-wrapped plastic film found over the cap on some bottled water brands as an identification of authenticity.
It is not beyond the capability of even comparatively small ‘fake’ water operations to produce convincing reproductions of original brands, and for overseas visitors these can be particularly difficult to identify when lacking familiarity with the real product.
In 2015 a group of four Vietnamese nationals in Laos were caught  producing fake Tigerhead bottled water by filling old bottles, and then repackaging them with new caps and plastic wrappings. The counterfeit components  (including 30,000 fake caps) weren’t exact replicas of the original product, but they probably would have passed cursory inspection, especially if you’d never seen the real thing before.
For travellers without knowledge of legitimate bottled water manufacturers at their destination, large scale counterfeiting operations that focus on major national brands may create an additional hurdle when trying to select a safe supplier. There’s nothing like seeing a local drinking a highly advertised brand of bottled water to suggest that following their example would be safe practice, but keep in mind that counterfeit bottled water is primarily designed to fool locals; the chance of a non-local spotting small packaging differences may be slim. An overseas traveller almost certainly won’t be presented with the real product to help in their decision.
As an example of fake bottled water production on an industrial scale, in late 2016 a factory in Crown Mines, South Africa, was raided by police  who found an illegal operation counterfeiting Valpre bottled spring water. According to its owners, Coca Cola, Valpre is South Africa’s “largest-selling” bottled water. At the factory, where water was being sourced from a fire hydrant, the police found 450,000 bottles already filled, 500,000 empty bottles, and a further 200,000 bottles in the process of being labelled, but they admitted at that time they didn’t know how long the fraudsters had been operating . This type of operation would have no problem in producing a convincing tamper evident seal on counterfeit water bottle caps.
The extent of ‘fake’ and counterfeit bottled water is unknown, but in September 2010 a state-controlled news agency reported that “Sales of mineral water in Russia stood at almost $1.9 billion last year. On average, about 30% of all mineral water sold in Russia is counterfeit, but for some brands the figure exceeds 70-80%” .
In 2016 the Commissioner General of the Kenya Revenue Authority stated that “The water and juice sector is one of the fastest growing industries in the country but statistics indicate over 60 per cent of the products are illicit.” . Similar figures have been previously reported in the huge Chinese bottled drinking water market  .
Numerous further examples of ‘fake’ and counterfeit bottled water production are listed here, and it is sadly inevitable that these won’t be the last of such cases.
Encouraging reliance solely on the basis that a bottle has a plastic cap with an intact tamper evident seal may be placing travellers at unintended risk, if they are not also advised to be aware that not only can such features be easily replicated, but that they routinely are.
 Victoria State Government, Australia. “Food safety while travelling”. Retrieved 24 April 2018.
 Government of Canada. “Statement on Travellers’ Diarrhea”. Retrieved 24 April 2018.
 U.K. National Institute for Health and Care Excellence, Clinical Knowledge Summaries. “Diarrhoea – prevention and advice for travellers”. Retrieved 24 April 2018.
 U.S. Centers for Disease Control and Prevention. “Managing Travelers’ Diarrhea While Travelling Abroad”. Retrieved 24 April 2018.
 J&C Services. “Producers Of Fake Drinking Water Caught”. Retrieved 24 April 2018.
 Food and Drug Administration, Laos. “Fake Tiger Head Drinking Water”. Retrieved 24 April 2018.
 SABC News via YouTube. “Fake Valpre Bottled Water Plant Found In Johannesburg”. Retrieved 24 April 2018.
 Aziana Mag. “Fake Bottled Spring Water Has Been Uncovered in Johannesburg”. Retrieved 24 April 2018.
 Sputnik News. “Almighty set to ‘guarantee’ quality of mineral water in south Russia”. Retrieved 24 April 2018.
 The Star. “60 per cent water, juice in Kenya is counterfeit – KRA”. Retrieved 24 April 2018.
 Food Safety News. “China’s Food Safety Issues Worse Than You Thought”. Retrieved 24 April 2018.
 chinadialogue. “China’s bottled water: the next health crisis?”. Retrieved 24 April 2018.