Well, if I don't have clean drinking water, but I have access to the Internet, it wouldn't be so hard to track down some filtration equipment. I'm sure they are twelve a dozen on ebay.
The average visitor to the LSM doesn't even know what not having clean drinking water is like. They probably think that it's OK, you just buy the bottled stuff from Sainsbury's. The question is really misleading, because of the hidden implications. In a society which cannot provide clean drinking water, your biggest problem will not be the lack of internet.
It's like asking what is more important to you: your shoes, or your <insert favourite smartphone>. I bet people would say their phone, because they can't even conceive of a situation in which they don't have a shoe. If you take the question literally, i.e. choose between otherwise completely equivalent situations, one with a missing shoe and the other a missing phone. Obviously, my shoe is £30, my phone is £300. But choose between being a tramp on the street without even a shoe, and a middle class couch potato who just about cannot afford a £300 phone, obviously the latter...