Oxfam New Zealand says there still isn't enough education in the Highlands region in Papua New Guinea about basic health and hygiene, like the need for hand washing.
Its communications manager, Jason Garman, says Oxfam is undertaking a new water hygiene and sanitation education programme in Gembogl district.
He says he met one family that carries 35 litres of water daily from a dirty, muddy stream for their water supply, and they say there is only enough water to drink and cook with, so they don't wash their hands.
Mr Garman says that's why it's so important to set up not just a clean water supply near homes, but to provide toilets and basic health and hygiene education.
"If they just have clean water and they don't have toilets, there's still going to be sickness in the village. If they have toilets but they still don't understand that they really need to wash their hands after they're in the toilet, and they need to cover their food and raise their food off the ground when the animals are walking, then they'll still have sickness in the village. But the three of those together, evidence shows that it decreases the incidence of water-borne illness by as much as two-thirds."
Oxfam New Zealand's Jason Garman.