What would you say if I told you that all the water you drink all day, doesn't necessarily mean that your body is hydrated?

Your body does need water, of course, but more importantly your diet needs to include wet foods that contain high levels of minerals:

Examples of this include:

Porridges
Soups
Stews

To help out with this:

Make sure you include enough saturated fats in your diet

Try to reduce the amount of dry/drying foods and drinks you are consuming, such as dry toast, onion and garlic, coffee, chilli, alcohol, sugar and carbonated drinks.