Last play through I noticed that the upper right also shows you an amount of water. I assumed this meant the amount of water you had available to your duplicants, and so I started to keep an eye on it to track how much water I was using as I went through the cycles. Originally it seemed fine in that it was gradually decreasing, but then I started noticing it jump up and down by quite a bit. I never *saw* it change by a significant amount, but I would check it a few cycles later and it would be +/- a significant amount. It wasn't clear why it was going up or down so much, I wasn't doing much exploring at the time, so I'm not sure if it's broken or I'm just interpreting it correctly.
Does it indicate all water visible on the map? Water accessible to your duplicants? Something else? A hover tooltip would fix my confusion and help me understand if it's broken or inaccurate. Right now it just says 'available water'.
Play the game and watch the liquid indicator in the upper right corner.