Can you get dehydrated from urinating?

No. Once urine has been formed the water will not be of any use to your body and all you can do is urinate it away. If your urine is any darker than pale yellow this can indicate that you are dehydrated and should drink more non-alcoholic drinks. YES! if you do not replace the fluids that you lose by urinating you will get dehydrated. In a pinch you can actually drink your own urine but I would go for bottled water first.