Some expensive home setups have methods to track your water usage so that you will not end up with a huge water bill at the end of the month, if you want something similar but can’t afford the whole deal, you could always try and come up with one yourself, which is what some folks out there did. They used a Koolance flow meter, normally used to measure coolant flow into PC liquid cooling systems, turning it into a cheap $20 sensor and paired it with a Wi-Fi-enabled Arduino. With that, they were able to use an iPad as a display to see how much water you’re using, which apparently resulted in some significant water savings. The details of the project are available for download online, giving you something to do over the weekend if you’re bored.