There is no transmission vacuum hose. That is a vent hose.
The vacuum hose should connect to the back of the intake manifold.
From the booster, to a vacuum source on the engine.
At the Nico website
Your question is to vague to answer. If you connected a vacuum hose to a water hose you would be ingesting water into the engine.
You can get a vacuum hose routing diagram for a 1998 Nissan 200SX SE-R from the dealership. You can also order one from the auto parts store.
There are several vacuum hoses. They are the small black tubes that connect things.
Depending on Yr/Make/Model, it usually connects to the intake manifold, TB or a T fitting in the vacuum hose to the HVAC.
that is a vent hose. it hangs freely. does not connect to anything.
The vacuum diagrams are too large for me to post here. But you can get them at the Public Library in the Reference Section.
You can check junkyards,eBay, and other sources.
vacuum hose from left side of carb. goes to egr