A group of researchers in South Africa has developed a filter that can purify water straight from the bottle.
It sits inside a tube that can be fitted on top of a bottle and purifies water as it is poured on a cup.
The designer behind the filter, Dr Eugene Cloete, from the Stellenbosch University in South Africa, says the filter is only as big as an ordinary tea bag.
He says the product is cost-effective and easy to use.
"We are coming in here at the fraction of the cost of anything else that is currently on the market," says Dr Cloete on BBC World Service.
According to him the filter will not only stop harmful bacteria from getting into the water, it will also kill them.
"We cover the tea bag material with nano-structured fibres, and instead of tea inside the tea bag, we incorporate activated carbon.
"The function of the activated carbon is to remove most of the dangerous chemicals that you would find in water."
He says that the function of the fibres is to create a filter where harmful bacteria is physically filtered out and killed.
According to the World Health Organisation the number of people who can access clean drinking water has been improving steadily across the globe. But there are millions of people - many in Sub-Saharan Africa - who still do not have access to drinkable water.