Alkalinity is the ability of water to neutralize acids. Total titratable alkalinity is a measure of primarily three types of alkalinities present in a water sample: hydroxides, carbonates, and bicarbonates. Alkalinity in water can be the result of contributions from common chemicals including carbonates, bicarbonates, hydroxides, phosphates, borate and organic acid salts.
The alkalinity of a water sample indicates its ability to resist pH change. The amount of alkalinity in water is mostly due to the bicarbonate/carbonate present. A low alkalinity level indicates that the water is susceptible to pH changes, while a high alkalinity level indicates that the water will be able to resist pH changes. Alkalinity can also be used to determine the corrosive capacity of water and can provide an estimation of water hardness.