Wasting water is not a wise idea. Unfortunately, many of us do it unknowingly. Taking long showers is one way to waste water. You could always buy a smart device to monitor your shower use or build your own. Chris Miller, Mayo Tobita, and Sarah Wever have a project on Instructables that shows you how to build a simple device to monitor your daily shower use.
The device detects when you enter the shower. It turns yellow to give a warning when you are about to hit your time limit. Here is the fun part:
Once you have passed the 10 minute limit the device intercepts you shower time playlist and begins to blast Nickelback with the only way to stop it being to turn off your water.
You are going to need an Intel Edison, a Grove Base Shied, a Grove button and a few other parts to get started. All the instructions for this DIY project are available here.