Some substances of health concern have effects on the taste, odour or appearance
of drinking-water that would normally lead to rejection of the water at concentrations
signifi cantly lower than those of concern for health.
The concentration at which constituents are objectionable
to consumers is variable and dependent on
individual and local factors, including the quality of
the water to which the community is accustomed
and a variety of social, environmental and cultural
considerations. Guideline values have not been established
for constituents infl uencing water quality
that have no direct link to adverse health impacts. However, guideline values have been
established for some substances that may cause taste or odour in drinking-water at
much lower concentrations than the guideline value because there is such a wide range
in the ability of consumers to detect them by taste or odour. In the summaries in this
chapter and the fact sheets in chapter 12, reference is made to levels likely to give rise
to complaints from consumers. These are not precise numbers, and tastes or odours
may be detectable by consumers at lower or higher levels, depending on individual
and local circumstances.