Where does the water come from?

Question

Edit : I am talking about the water on the surface of earth, such as oceans and seas. How did it occurred?

In: Chemistry

Answer 1

Comets & asteroids over billions of years.

also, deep within the mantel there are minerals like ringwoodite that at some point during their life decay and under the right circumstances form H2o

https://en.m.wikipedia.org/wiki/Ringwoodite <-