Water bottle-lugging tourists are fixtures around the globe, as fear of Montezuma’s revenge and Delhi belly have led to travellers’ constant purchasing of bottled water, particularly in developing areas where the bacteria that cause stomach ailments runs rampant.

But all that plastic waste is a creating quite the trash heap, and if you’re looking to reduce your plastic footprint, hiking in remote areas or simply stuck in a hotel with only tap water you’ll need another option. Thankfully, there are plenty of them.

Any of these eco-friendly techniques or devices will zap the contaminants in your water, including parasites (such as giardia), bacteria (e coli and salmonella) and viruses (hepatitis A and norovirus). If you see dirt and other particles in your water, pre-filtering through any mesh or cloth item is obviously a good idea too.

This age-old, sure-fire water purification method is cheap and easy, provided you have access to a heating source and time to kill. It takes a while for that scalding water to cool down to room temperature.

Boiling for one minute will kill all waterborne pathogens -- bacteria, parasites and viruses – though wait three minutes if you’re at an altitude of 6,000ft or more. The US Centers for Disease Control and Prevention recommends adding a pinch of salt to help with the taste.

Iodine or chlorine tablets are lightweight and easy to transport, and they won’t break the bank. The chemicals take about 30 minutes or longer to work, but similarly to boiling, the biggest con is the unpleasant taste. Travellers often mix in flavoured drink packets to make the resulting water palatable. A few other issues: the chemicals may not kill certain stomach-ailing parasites such as cryptosporidium, and for pregnant women, iodine is off-limits.

Filters, often made out of ceramic or carbon, block microorganisms as they strain the water -- similarly to the Brita water pitchers used in many homes. But many filters only block parasites and bacteria, not viruses like hepatitis A, so international travellers should make sure their filter is also a purifier where water is filtered and then chemically treated. The outdoor recreation store REI recommends the chemical-free purifiers from First Need, which quickly pump out instantly-safe water without the chemical aftertaste..

Bottle filters
These all-in-one units, such as those from the brand Katadyn, filter and treat water as you sip it. Just add water to the bottle and with each squeeze it’s sent through a filter of iodine resin and carbon. It is very convenient for a single traveller, and it is usually an affordable option. But this solution only works when sipping slowly, and there is still a chemical taste to contend with.

UV Light
Ultraviolet light is pretty powerful stuff -- so powerful that it can neutralise all forms of stomach ailment-inducing pathogens, even viruses. These UV purifiers are about twice as expensive as bottle filters, but they quickly render water safe without the use of chemicals, and without an odd aftertaste. Travellers only have to swish water over the light in a water bottle, or stir the small UV wand like those from SteriPEN in a water glass for a minute or so. As a downside, the purifiers take batteries, so pack extras.

Lori Robertson writes the Ethical Traveller column for BBC Travel. You can send ethical dilemmas to bbcethicaltravel@gmail.com.