When you need your tap to run hot water for different reasons, such as dishwater (yea, I'm one of those who still does that), you waste water down the drain while you wait for it to turn hot, right? Well, I have one solution that saves on this water waste.
When you're ready for hot water, just run the hot tap into your coffeemaker's water reservoir or carafe, whatever it is you have. By the time you have filled it, you have hot water.
You could go ahead and add your ground coffee and your pot is ready and waiting for it's next brew whenever.
Just imagine how much water you can save over a year's time. It really adds up when you think about it.
Now, go get those dishes washed.