French engineer Gabriel Della-Monica was at the gala Consumer Electronics Show with a smart showerhead created to stop precious water from going down the drain.

Della-Monica had his four daughters in mind and the hours they spend in the shower when he set out to create a showerhead that lets people know when it is time to turn off the tap.

Last year, he founded Smart & Blue, the France-based startup behind the Hydrao smart showerhead one of a sea of gadgets on display at the Consumer Electronics Show, which continues through Saturday in Las Vegas.

"I created Hydrao to with the idea in mind that I could educate my little girls on the importance of saving water," Della-Monica said.

"I needed to make bath time fun and educational in order for them to develop good habits."

He added that after seeing the positive effects, "I decided to bring the same knowledge and excitement to other families around the world."

Hydrao showerheads track the flow of water, with LED lights starting out green and then changing from blue to red as use climbs. The shower head light flashes red when the 50-liter mark is breached.

Electricity for the lights is generated by mini hydro power plant in the showerhead, so no batteries are used.

Hydrao showerheads can connect wirelessly to smartphones or tablets running on Apple or Android software, and come with applications that let people set up personal profiles and track water use over time, Claire Curaba of Smart & Blue told AFP.

"It helps you save water by making you aware of your habits," said Curaba, who noted that it also lets parents see how much water their offspring may be wasting in the shower.

"It stops the shouting of 'Are you done yet?' through the bathroom door."

First-generation Hydrao showerheads produced after a successful crowd-funding campaign have been snapped up, and a second-generation expected to be priced below $100 is in the works, according to Curaba.