World Vision says the number of people worldwide without access to fresh water has dropped markedly in recent years, but the toughest part of the job lies ahead.
World Water Week this year is focused on development, specifically the United Nations' Millennium Development Goals, set in 2000 and targeted at addressing extreme poverty.
World Vision NZ CEO Chris Clarke says efforts to bring fresh water to the world so far have been a "good news, bad news story".
"A few years ago we were talking about 1.2 billion people who didn't have access to water – now that's down to close on 660 million," he said on the Paul Henry programme this morning.
"But it's that last 660 million that in some ways are the hardest to reach – they live in rural areas, they live in mountainous areas – so the job's not done."
In some parts of the world, people – including children – spend most of their day looking for water, meaning there's no time left over for anything else, such as education.
"Where we've managed to put in wells and give safe water sources, what that means is children aren't spending their time needlessly walking back and forth – that's time they can put into school," says Mr Clarke.
"We know that if we can educate a girl, the impact of that on the community will be profound."
But first, people need to be taught how to keep the water clean, otherwise it will all be for nothing.
"We actually teach them to wash their hands just using little taps, and then we bring the well to the community. That's what the community wants, but if you don't also deal with the sanitation issues and the hygiene issues, you will still have thousands of children dying."
Communities also sometimes need to be shown how to maintain their vital lifeline.
"Sadly there are quite a few wells that no longer function," says Mr Clarke. "The wells that don't function are usually dug by others and just left – the wells that continue to function are where the community owns the well, and they set up water boards, they pay taxes to use the water. What they do with that money is maintain the well."
Without functioning wells, the hunt for water is not only time-consuming, but dangerous.
"That water is often shared with animals, so it's not the greatest of water, and then they bring it home – and because it's so precious they don't use it to wash their hands, they don't use it for sanitation – they just use it for cooking and drinking. Of course that leads to terrible diseases and terrible impacts down the track," says Mr Clarke.
"That walk to the water source is itself often fraught with danger because there are issues with human trafficking, issues with wild animals. What we're trying to do is bring water sources much closer to communities and of course make that water clean."
The best way to help, says Mr Clarke, is simply to sponsor a child, which has spinoff benefits for entire communities.
"That money will go for water to the community, and that means that girl who was collecting water can now go to school, so it goes to education… and also for good healthcare."