Even the most devoted environmentalist will likely confess to taking long, hot showers on occasion. One possible reason (besides the comfort factor) is that, unlike with electrical outlets, there are few products to help users gauge the amount of water being poured out of a showerhead. That's where the Waterpebble comes in.
The device is placed at the bottom of the shower, where it keeps track of all the water being poured down the drain. If users take ultra-long showers, the Waterpebble's LED light glows red. If water is being saved, the device glows green, and if just enough water is being used, the Waterpebble glows orange. Instead of holding all users to the same standard, the device keeps track of how much water is used during the first shower after it is activated. Every shower after that is judged based on how much water it uses compared to that first shower.
Best of all, the Waterpebble isn't just another well-designed concept device. It's on sale here for $5 plus shipping.