Research shows fairly consistently that most people are in a permanent state of dehydration, and that the sensation of thirst is not a good guide to how much you should drink....
Well, as it is is such an important topic, I checked my references (i.e., those I trust with my own health; make of that what you will) and found no particular guide to how much is appropriate, but a lot on why we should drink more! There's also the quack mendicants who send news letters challenging medical knowledge by asking questions like "can anyone specify how much we should drink?" to which the obvious answer is no! It depends on circumstances.
Guys, I'm running out of steam again, but, CR, irrespective of measures, your downput seems to me healthier than most, so your only issue should be the quality of the water you drink. Most water, whether bottled or tap (=faucet) is contaminated; the only sure bet is distilled or deionised water (tasteless, but you can always add {organic} fruit juice?)