What is the relationship between gravity and water on earth's surface

the relationship between gravity and water on earth's surface can be explained through the idea about tidal forces.

In general usage in celestial mechanics, the term ''tidal force'' can refer to a situation in which a body, tidal water for example, is mainly under the gravitational influence of a second material, for instance, the Earth, but is also perturbed by the gravitational effects of a third body which is the Moon for example.