Sometimes it’s lighter, sometimes it’s darker, sometimes it’s clear, sometimes it’s cloudy. So what’s causing the changes, and what do they say about your health? We asked London-based physician Lauren A. Bumby, MD, what to look for when you “gotta go.”

Your urine can give you a general idea about your health status—more specifically, your hydration. A lighter color is definitely better than a dark color. When our urine turns dark (like the color of iced tea), that either means you are dehydrated or your kidneys may not be working properly. Our urine turns dark when we are dehydrated because the kidney regulates our water balance. It senses that we need to retain water and therefore it decreases the amount of urine we make. The less water we get rid of and the less water that we have in our urine, the more concentrated the urine becomes and it turns darker. Ideally, urine should be either light yellow or clear.