Sentence:  In the second sentence if drinking water <WSD>is</WSD> a gerundial clause and without drinking water is roughly equivalent in meaning to unless I drink water , there will be stronger stress on water than on drinking ; but if drinking is a gerundial noun modifying water and without drinking water is equivalent to without water for drinking , there will be stronger stress on drinking than on water . 
Meaning of the word marked with <WSD> tags:  be identical to; be someone or something