Every water heater has what is called a standing pilot, a little tiny blue flame that's visible if you're kneeling down in front of the water heater. It's visible, you can see the flame. If you don't see the flame, it's going to be out, and water heaters today come equipped with an empisal letter, just like your gas grill. What happens is that you have to light the water heater, hold the pilot switch down and click a button, just like your gas grill. If you don't see your pilot, if you don't see a little blue flame, it means your pilot's out and needs to be relit.