Ford is taking an idea suggested by two young German siblings and is developing a system of reusing rainwater to power windshield water jets.

Daniel and Lara Krohn were traveling in the family car last summer when the heavens opened. Their dad, Gerd, was driving and when he tried to clear grime smears off the windshield, he found the washer reservoir was empty and the windshield just got dirtier.

“It was a downpour,” 11-year-old Daniel says. “There was water everywhere – except in the windscreen wiper reservoir. My sister and I thought this was really funny and then the answer suddenly seemed obvious. Simply reuse the rainwater.”

“We couldn’t believe that no one had thought of it before,” adds 9-year-old Lara. “To try it out, we took apart our toy fire engine and fixed the pump to a model car inside an aquarium. Then we added a filtering system to ensure the water was clean. It just worked really well.”

The clever kids’ idea to capture raindrops and reuse them won first prize in a local science competition, and now Ford has developed the system to work on a test car.

Engineers have installed a fullsize device into a Ford S-Max test car where, to collect the water, rubber pipes connect the bottom of the windshield to the reservoir.

Theo Geuecke, supervisor-body exterior hardware at Ford of Europe, says: “Daniel and Lara’s idea has been staring drivers in the face for decades, and it has taken one moment of ingenuity to bring it to life. In less than five minutes of rainfall, the washer reservoir is completely full.”

Water used by vehicles is expected to increase because the additional cameras and sensors used in advanced driver-assistance systems also must be kept clean. Ford engineers are working on ways to capture water, via rain and condensation, including On the-Go H20 – a way of gathering moisture from the air and filtering it into drinking water.

Research suggests drivers use about 5.3 gallons (20 L) of water each year to keep their windshields clean. With 291 million cars on European roads, if such a “Krohn” system were in every car, it would save almost 1.6 billion gallons (6 billion L) of water each year.