There are very few things today still being made to withstand the test of time. This is one of them. The new Marathon Water Heater. One of the big things people notice about the new Marathon Is all the little things it has. Some things you see right away - like its tough but lightweight polyethylene outer shell. Others don't become apparent until you've owned a Marathon for a while - like the fact that it is incredibly energy efficient - or the value of your Marathon water heater being warranted not to leak for as long as you own your home. Sounds Good. And it is. Dozens of these little touches add up to one thing: real long-term value.