Dumb question: is this referencing the color in the toilet bowl, when diluted with water? If so, how much water, because different kind of bowls can have very different amounts of water. Or pure?
Fairly dumb answer, it doesn't really matter. If it's dark you should try to drink more water. It should be light enough that it doesn't really effect the water in the toilet bowl much at all.
I guess if it's a huge amount of water you could not notice the color. If it's clear then it's clear though. If it's not, you'll probably notice either place unless it's a something crazy. I guess just look at the stream if that's your position.