Here's a question for you, though: if I cast silence on the water in a bucket, then dump the water on a spellcaster, does the silence work? Given that it would soak into their clothing, it would be pretty tough to remove!
That idea is so awesome, if I were your DM I'd be tempted to say yes.
However... the only time I can think of off the top of my head that this issue was tackled anywhere in the rulebooks was the fiend of possession which originally has the ability to possess an object and it isn't until several levels later that it gains the ability to possess a non-solid object like water or the air. This implies to me that water is not a valid target for "object", though it's far from definitive.
I've only got the core 3 on me though and I can't find anything more specific on this issue though.
If I was your DM I'd be forced to say no, but I would recommend researching a new spell (at a higher level) that could do exactly that as it is AWESOME!