What would cause an oil fired hot water heater to give out brown water even after draining out and refilling?

The heater is less than 10 years old. It was drained when water was shut down for winter and refilled four months later. There was no water problem before this. Is currently beening drained weekly to lessen brown water. We have very hard water, but have never encountered this before. Also causes itchy skin.

What would cause an oil fired hot water heater to give out brown water even after draining out and refilling?
If you drained it and left it full of air it would have corroded, if it was not glass lined. Now, the best thing you could do would be to run a lot of water through your taps to flush it that way rather than drain it. Or hook a garden hose to the drain connection and run water for a while without emptying the heater.
Reply:It sounds like mineral build up. If you have your own well, try adding a sand filter after the pressure tank, but before your hot water heater and water softener. You can buy or rent these from Culligan Water or Rain Soft to name just two.