Does Water Flow Create a Suction in Supply Pipes?

[Idea04]

Homework Statement

If you have a supply line of water running from one tank to another tank.
And you started to drain the water out of one of the tanks.
Would the downward flow of water create a suction or low pressure in the supply tube?



. Relevant equations[/b]

The Attempt at a Solution

 

[Idea04]

Any one know the answer to my question?