Now, a South African company has come up with a new device that eliminates part of the toil and exploits one of the world's last great untapped sources of power - the energy of children at play.
The Playpump pumps ground water from bore holes into sealed holding tanks but, instead of using traditional hand pumps to draw the water - a tedious task that usually devolves upon women and girls - the Playpump is powered by a brightly painted children's roundabout.
Trevor Field, a British immigrant who heads the Playpump company, says childpower was dreamt up by Ronnie Stuiver, an Afrikaner engineer whose main business was drilling bore holes in remote areas of South Africa prone to drought.
He was drilling in the former Xhosa homeland of Ciskei when he had a brainwave. "There was dust everywhere, so of course all the village kids came along and crowded around and started pushing each other into the hole and all that, and he suddenly thought there must be some way of using all that energy."
Mr Field says that the Playpump can pump 1,400 litres an hour into an overhead storage tank, whereas a standard hand pump will only pump 150 litres an hour to ground level, where it cannot be stored sanitarily.
The low maintenance merry-go-round turns as easily as a standard playground fixture. For the women, many of whom still have to haul water weighing up to 60 kilograms back to their homes, their children's overabundant energy for once makes life a bit easier. It seems that sometimes what goes around really does come around.
Playpump says it has already sold 60 units even though the installation cost of 30,000 Rand (pounds 3,000) is much higher than the 10,000 Rand cost of installing a standard hand pump.
The company bridges the cost gap, and turns its own profit, by means of a second novel idea. The 5,000-litre tanks into which the water is pumped are prominent landmarks in low-rise villages and townships so Mr Field, a veteran advertising man, hit upon the idea of selling advertising space on the towers.
"We sell three-year contracts to people selling things like soap products, mealie [maize] meal, flour, things like that," says Mr Field, who was born in Birmingham.
"The water pump is a natural gathering point for the women of the village and the pump is a community service, so where better to advertise?"
So far the Playpumps are limited to South Africa, but the company hopes to find sponsorship or backing to export the idea to the rest of Africa and the developing world. Mr Field believes the potential of the market in the Indian subcontinent is huge.
One of the first of the pumps to be installed is in the township of Daveyton, on the edge of Benoni, 30km east of Johannesburg, where it provides irrigation water for a community market gardening project.
While the core energy source is Thabong pre-school children aged three to six, Crosby Thobela, the project leader, says he has found himself with more power than he needed. "This is the only roundabout in the whole of Benoni," he said, watching the Thabong children swarm over the merry- go-round on a morning break, "so we have to make arrangements for all the kids in the area to play on it. The kids from the primary school over there will be coming down here at 1.30, after these children go home."
Mr Field says most communities had never even seen a roundabout before their Playpump arrived - "they didn't even have an African word for it". Even the women have been known to take a few turns on the merry-go- round when the children aren't around. "They won't admit it but they do," he says, lowering his voice. "If you asked them they would say it's beneath their dignity."Reuse content