Science does not give a clear answer about the origin of water on Earth. The theory is that our water came from comets and asteroids sent to Earth. Early magma oceans interacted with atmospheric hydrogen, resulting in the formation of water.
The study of zircons has shown that liquid water must have existed 4.4 billion years ago, very soon after the formation of the Earth. This required the formation of an atmosphere. The theory of the cold early Earth covers a range from 4.4 billion years to 4.0 billion years. Based on the various theories of the origin of water on the planet, it can be assumed that water has two phases of formation.
Primary water, formed due to the direction of cosmic objects containing water from the Universe.
Secondary water, formed as a result of the water cycle in the atmosphere.
Water once began to penetrate the soil in the form of precipitation and seeped through various layers of soil and rocks over a long period of time. Taking into account modern anthropogenic load, water obtained from the water cycle in nature is subject to chemical and bacterial pollution.