Final answer:
Water samples for different quality tests are collected from the water supply and distribution points.
Step-by-step explanation:
The collection of water samples for various tests, including bacteriological, turbidity, THM (Trihalomethanes), chlorine residual, and tests for taste, odor, color, and heavy metals such as lead and copper is typically carried out for monitoring water quality. Bacteriological samples are generally collected from points of use or distribution systems.
Turbidity samples, which measure the clarity of water, are often collected along with bacteriological samples. THM samples are taken at various points in a distribution system because these compounds can form as a result of chlorine treatment reacting with organic matter in water.
Chlorine residual samples are vital in determining the disinfecting level present in the water, which can be measured through the redox titrimetric method. For the assessment of heavy metals like lead and copper, samples are typically collected from consumers' taps following specific sampling protocols laid out by regulatory agencies.