Typically, values for ambient water quality are calculated using the amount of total dissolved solids (TDS); percentage dissolved oxygen (% DO); dissolved inorganic nitrogen (DIN); dissolved inorganic phosphorus (DIP); and abundance of Escherichia coli (E. coli) in a volume of water sampled from water bodies in an area. Categorical values of this value specification, such as 'good', are specified based on the impact the parameters listed above have on normal ecosystem functioning and human health.

ambient water quality

A value specification about the quality of water bodies in a given area.

Impact and damage to ecosystem functioning and health are difficult to define without the norm specified. This could be formulated like an increased risk of a portion of water from a water body realising its hazard disposition towards an ecosystem or living human.