I had my urine checked for uti, no infection, but dr said it was concentrated. i drink at least 2 liters of water a day.?

Lose water other way: Urine concentration is not directly proportionate to fluid intake. If you are constantly sweating at work then you will have lost most of your fluids in your sweat, so you urine will then be concentrated. You should attempt to increase your water intake to the point that the urine is clear. There could be other things in the urine as well, so get an urine analysis and follow up with your pcp.

Concentrated urine: The 'spec gravity' is a measure of the concentration of excreted molecules in your urine, and your doc was probably commenting on this. Urine dips aren't perfect -there's some variability with how you read the result. So when i see a slightly high spec grav in an otherwise healthy person with no kidney problems, i'm not overly alarmed. You can get a urinalysis to verify.