Everyone knows that water is crucial for the heath of the skin, but what about the hair? Skin is a living organ of the body, but hair is dead. Why should how much water a person does or doesn’t drink affect it? But of course, water does affect hair as it affects every other system in the body. Here is how and why.

Hair itself may be made of dead cells but it arises from living tissue called a hair follicle. This is a tiny sac found in the scalp that’s lined with skin cells and lubricated with sebaceous oils. The follicle needs water to bring nutrients to it, and remove wastes. This allows healthy hair to grow. People who don’t drink as much water as they should often notice that their hair is dry and brittle. Moreover, if they suffer some extreme stress, their hair may stop growing or even start to fall out.

Water is also important in cleaning the hair, but hot and cold water behave differently. Hot water is better than cold water when it comes to rinsing away dirt and old oil, but it causes the pores in the hair to open up. Though this allows moisturizers and conditioners to get into the hair, it can also make the hair brittle. While cold water may not get rid of as much dirt, the pores of hair rinsed with cold water don’t open up, and the hair is stronger. Because of this, some experts recommend shampooing and conditioning the hair with hot water and rinsing with cold water.

Another concern people have when it comes to water and hair is whether the water is hard or soft. Hard water has a lot of minerals in it. These minerals are largely calcium and magnesium. They are good for overall health, but they are not good for the look of the hair and can leave it dry, brittle and dull. Some people install a water softening system to combat this. It not only spares their hair but keeps laundry from looking dingy when it comes out of the washing machine. Other experts recommend a chelating shampoo, which takes the minerals out of the hair. Still others have found that washing the hair with purified bottled water or even distilled water avoids the damage done by water that's full of minerals.

Whether it’s taken internally or externally, water is vital to the health of the hair.