Hair porosity is simply your hair's ability to absorb and retain moisture.
There are 3 ways you can determine where your hair falls in the porosity spectrum - low, normal, and high porosity.

Characteristics of Low Porosity hair.

 *Natural oils sit on hair rather than penetrate it
*Curls take longer time to dry
*Products tend to sit on hair rather than absorb.

Characteristics of Normal Porosity Hair

*Easily absorbs and retains moisture inside the cuticle. *Curls are full of bounce and elasticity.
 *Requires low maintenance.
 *Holds style well and can be colored with good results.

Characteristics of high Porosity Hair

*Curls dry quickly
*Curls are often frizzy
*Curls absorb water quickly and easily. However, it requires more products.

Low porosity hair has very compact cuticles which makes it hard to inject water in the hair shaft, even though it doesn't retain the moisture once it's absorbed.
 Solution: To raise the the hair cuticle, use deep conditioning treatment with the help of hooded dryer or a steamer. Apply products when hair is damp. Use clarifying shampoo to get rid of product buildup and then follow with a moisturizing sulphate free shampoo.

Normal porosity hair has compact cuticles that easily allow moisture in.
Treatment:  Continue your regular deep conditioning with good products.

 High porosity hair is dry, parched, and thirsty. It needs products that helps it maintain as much moisture as possible.
To hydrate your high porosity hair, follow these routine: Use minimal or no heat. Let hair air dry. Incorporate regular deep conditioning and rinse with cold water to help seal your cuticles and prevent frizz. Detangle with wide tooth comb. Lastly, drink lots of water. It is recommended that you drink half of your body weight per day. Hope these helps.