Have you ever drank a glass of water and noticed an unexpected sweetness? Water, essential to life, is often overlooked in favor of sugary alternatives like soda, smoothies, and alcoholic beverages. Even athletes favor sports drinks such as Gatorade over nature’s original sport drink. Many people consider it bland and even a chore to drink. However, some people have come to realize that sometimes plain water isn’t tasteless and is rather sweet. Why is that?

To understand water’s taste, we must first understand that tap water is not completely pure. “Tap water naturally contains minerals, such as calcium or iron, that can produce a sweet taste when found in larger quantities or when consumed by those with more sensitive palates,” a blog from Culligan Quench, a company that manufactures water-related machines, states. As a result, when people drink distilled water, which is pure H2O with no other minerals, it tastes flat because there are no materials that give it its usual taste.

Plumbing can also play a role, especially depending on which materials your pipes are made out of. Plastic and metal pipes both change the taste. Metal pipes can erode, releasing substances that affect taste, while plastic pipes, such as PVC or PEX, may retain chemicals that alter flavor. “When water flows through or sits in the pipes for a long time, you might notice a slightly sweet taste when you drink from the tap,” says Brian Gaughan, the CEO of Carroll Water. This is why many cities are concerned about replacing old, toxic pipes, because people will directly ingest those materials when they drink water that passes through them. Water can be contaminated from the source as well, also changing its taste. 

Of course, the easiest explanation is that it is just how you interpret it. Your own taste buds (the olfactory system) may be a bit “off” which explains your unique description. However, studies have shown that when you are thirsty, water seems to taste especially sweeter. This seems to be a survival design for the human body. Since water is so critical for human survival, it would make sense for our bodies to be created to like water. 

Water also seems to taste sweet after eating certain sweet foods. In 2006, scientists discovered the reasoning behind this. “When a water rinse removes sweet taste inhibitors [(saccharin and acesulfame-K)] from the inhibitory site, the sweet receptor is re-activated and the perception of sweetness returns,” the Monell Chemical Senses Center reports. Due to the physical act of drinking, water washes away residual sweet substances, some of which contain compounds that temporarily dull your taste receptors.  As these inhibitors are removed, your ability to perceive sweetness returns, making the water seem sweet. But in reality, it’s simply the water revealing the true taste of the sweet food you consumed earlier. 

So, the next time you reach into your wallet to buy a smoothie, think about the free sweet water that awaits you behind the counter. Your body doesn’t need “sweet” drinks all the time —sometimes plain water is just as satisfying.