Before we bought this house 3 years ago it was a rental for a number of years, and there's lots of evidence that the owners were the types of landlords who don't do any maintenance except for emergencies. So even though the water heater is only about 6-8 years old (they replaced it when the previous one blew up) and it's the same size as every other water heater we've had in our previous homes, we've noticed that lately we'll run out of hot water much earlier than we used to. My uneducated guess is that this is due to scale buildup in the water heater, from years of non-maintenance. So, two questions: 1. How can I find out if I'm right? 2. I only know about preventative maintenance on water heaters. Is there a way to remove scale once it's already built up?