More than 20 years ago, an engineer and senior designer dreamed up a solution to help people in rural areas carry out the neck-crushing, time-consuming but essential task of bringing home water from nearby rivers and community taps.

This basic chore, typically done by women and girls, occupies an estimated 200 million hours per day globally - time that could be better spent on other tasks or, in the case of children, in school.

South Africans Pettie Petzer and Johan Jonker decided to tackle this social issue, and came up with a better water bucket: Durable plastic water drums that can be turned into wheels - almost like wheelbarrows - through steel handles attached to their sides.

Called the Hippo water roller, the plastic drum can be easily pushed or pulled even over difficult terrain, and has a capacity of 90 litres - about five times more than a woman can carry on her head in a bucket.

By allowing users to push water instead of having to carry it, it can save many women and children in the developing world the pain and exhaustion of transporting their daily supply of water on their heads.

And because they can contain more water, the Hippo roller saves the number of trips villagers need to make. It usually lasts five to seven years.

Its name came from a survey done in South Africa, where passers-by were asked what they thought of the product. They said it looked "big" and "strong", "just like a hippo".

Today, the Hippo roller can be found in 21 African countries, and some 44,000 rollers have been distributed with the help of the Hippo Water Roller Project - making an impact on the lives of more than 300,000 people.