"Skitt" answers a question:

>>> Lately I've heard constructions of the following form:
>>>
>>> "The pitcher had water in...."
>>>
>>> My intuition would be to state that as:
>>>
>>> "The pitcher had water in it...."

> Yours is a good intuition.

>>> Is the "it" really unnecessary?

> Yes.

This seems contradictory.

If I'm saying this, I find the "it" necessary. But there are many similar
constructs where the analogous word isn't necessary ("a woman with a nice
dress on"), so I don't think it's surprising that some people would prefer
not to use it here.
--
Mark Brader, Toronto | "I don't have a life; I have a program." --the Doctor
| (Michael Piller, Star Trek: Voyager, "Tattoo")