What does 'it' refer to in this sentence?

Water will tend to leak from a pipe with equal facility in any direction and not just in the direction of the weight of the head of water bearing down on it.


the pipe


You've asked this kind of question before.

Ask yourself whether "it" is referential or just a dummy.

If it's referential, which noun phrase is the most likely referent? "Water", perhaps, or "pipe"?

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I know that "it" is not a dummy but referential in this sentence. However, I don't know whether it refers to 'water' or 'pipe'. I think syntactically 'it' can refer to the pipe, but I have no idea whether 'it' can refer to water or not.

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Now I know 'it' refers to the pipe. I understand why I was uncertain. Thanks.