On Wed, 13 Jan 2010 09:28:35 -0600, dpb wrote:

OK, so the only way you could do anything about it anyway is either thru
the top hatch anyway unless there's an access underneath somewhere.

There does not appear to be any access other than from the top.

How is/was the connection made; where's the line?

The well water comes in from the top of the leaking tank.

There is a four-inch fire-hydrant line connecting the two 5000 gallon tanks
near the bottom; so as the leaking tank fills, it fills the second 5000
gallon tank in parallel. Presumably that 4" line will will "almost" empty
the tank should we need to drain it. Each tank has a large 8'inch wide
circular handle on that four-inch line to isolate each tank from the other.

At about the 1/3 empty mark of the tank that is leaking, there is the water
outflow for the house. This steel outflow pipe is about two inches wide.
Presumably the house can only use the top 2/3 of the water in the tanks
while the unpressurized fire hydrant can use almost all of it.

I'd wager a new tank is in your future; you may be able to put it off
but likely not repairable.

I was afraid of that.