Electric water heater: OK to turn it off?

[LikeLakes]

Originally Posted by SailinAway

If I don't shut the valves, doesn't that mean the water is coming from the water heater, with the risk of bacteria??

If the valves are closed, why would there be air in the pipes? The pipes would be under pressure from the town water main, no?

To answer your question, with valves open you only get water from the tank if you open a hot water faucet, or push a mixing valve (kitchen sink for example) toward hot. You're right, close both valves and you've "trapped" the water in the tank. I'd still rather leave them open and pressurized, just from my experience with house piping and winterizing, etc.