PH

The symbol for the logarithm of the reciprocal of hydrogen ion concentration in gram atoms per liter, used to express the acidity or alkalinity of a solution on a scale of 0 to 14, where 7 is neutral, less than 7 represents acid, and more than 7 alkaline.

Precipitation

The condensation of a solid from a solution during a chemical reaction; rain, snow and other forms of water falling from the sky.

Potable Water

Water that is safe to drink.