Hydrogen ion concentration

What is Hydrogen Ion concentration (pH)?
pH stands for Hydrogen ion concentration and is a measure of whether a liquid is acidic or alkaline. The pH scale ranges from 0-14. Water with a pH of seven is neutral, below seven is acidic, and above 7 is alkaline. Extremes of pH can affect the palatability of water. In Drinking Water Regulations, it is defined as an Indicator Parameter.
What is an exceedance for pH?
The limit value set out for pH in the EU drinking water directive is a designated range of > 6.5 – < 9.5 pH units. Therefore, any result above or below this specified range is an exceedance for pH. How can a pH exceedance occur? High values indicate excessive acidity in a water supply whereas low values indicate excessive alkalinity. This is one of the more stable parameters, therefore, a change in the pH value of water would be immediately investigated as it could indicate a major event.