The team behind Hydrao is aiming to build awareness around these important resources, with an LED-equipped shower head that changes color when you're overstaying your welcome.

Over the years we have seen a number of tech-inspired solutions to cutting water usage in the bathroom. Showers that purify and reuse the water that goes down the drain, designs that atomize water into tiny droplets rather than pushing out larger ones, and illuminated shower heads that go from green to red when it's time to get out are just a few examples.

Hydrao follows the lead of this final approach, but does look to be particularly well executed. The shower head can designed to be screwed into a standard shower hose and is fitted with an LED light that's powered by the water flowing through it, so there's no batteries involved. It starts out as green when you first hop in, then morphs to blue once 10 L (2.64 gal) is used, orange once you hit 30 L (8 gal) and flashes red when you've used 50 L (13.2 gal).

It also connects with a smartphone app over Bluetooth, where users can create individual profiles to log showers and track overall water usage, customize the color configurations and set water savings targets.