Band 9: The diagram below shows how rain water is collected and then treated to be used as drinking water in an Australian town. Summarise the information by selecting and reporting the main features and make comparisons where relevant. You should write at least 150 words.

The diagram illustrates the process by which rainwater is collected in Australian households and purified so that it can be used as drinking water.

Overall, the system consists of several stages, starting from the collection of rainwater from the rooftops of houses, followed by filtering and chemical treatment, before the water is finally distributed for domestic use.

In the first stage, rainwater falls onto the roofs of houses and is directed into gutters. From there, it flows through underground drains, which transport the water into a filtering unit. At this stage, solid particles and other impurities are removed, ensuring that the water is clean enough to be stored.

The filtered water is then collected in a large storage tank. After this, it is pumped into a second tank, where it undergoes chemical treatment. The addition of chemicals removes harmful bacteria and toxic substances that may still be present.

Finally, once the water has been fully treated, it is delivered back into households through a pipe system and becomes safe for drinking purposes.