Urgent: Overflow leak.. Advise required.

[scherzo]

What has been said is correct. The water level will equalize in the DT and the overflow area.

One problem might be if you ever had a leak in the bulkhead for the overflow you wouldn't really be able to work on it. Your DT would slowly drain into that area.

The other problem may be if you had a leak in the bulkhead in the overflow area and the power went out for a long period of time, your DT would also empty into your overflow.