"Chris Lewis" wrote in message
...
According to PaPaPeng :
Too big to be a (water) pressure vessel.

On the contrary - before bladder-style tanks, seeing
pressure tanks this size isn't at all unusual.

Given the plumbing arrangement, I'll bet there used
to be a pump there.

Red sandy stuff inside? Could this be an old fashioned
permanganate tank used for removing dissolved iron? If the
stuff hasn't been replenished in _years_, it's not doing anything.

Is one of those lines direct from the pump?

Yes, the bottom line comes directly from the pump outside.