If you're not drinking enough fluids, your urine will be darker in color, and you will urinate less frequently. Checking the color of your urine is a practical way to identify dehydration. Your urine can turn dark if you're not drinking enough fluids or your body is trying to conserve water.
When this happens, your urine becomes more concentrated with waste products from the body, like sodium and urea. The goal is to have pale yellow urine, like the color of light straw. This is because other factors, like medications and B vitamins, can turn urine bright yellow.