Why water is renew-able?

Answer 1

The difference between a non renewable and a renewable resource is related to how fast we use it and how fast the environment can replenish it.

Non renewable resources are resources that we use faster than the earth can replenish. Coal and petroleum are some good examples of this because humans use both at a really rapid rate and go through gallons and gallons a year, but it takes millions of years to convert plant matter into fossil fuels like coal or petroleum, so if we continue using it at the rate that we have been we will eventually run out.

Renewable resources on the other hand are resources in which the rate that they are replenished in the environment is higher than the rate at which we use it. It other words if we kept using it at our current rate it would not run out. Water is an example of this because it is replenished at a higher rate than the rate we consume, as is solar and wind power.

Note however this line is not "cut-and-dry" trees are typically considered a renewable resource for example, but if we started cutting down trees faster than they reproduced they would be a non-renewable resource. It depends on both rate of use and the rate at which it is replenished. And these rates, particularly the rate of use can change.