The presence of rust in the water of Westfield is the reason for the change in colour.
The water of Westfield has reddish-brown substance. This reddish brown substance in the water is the rust which formed due to the chemical reaction between the iron pipes and the fertilizer substance present in the water.
Due to this reaction, the colour of Westfield's water is different from normal type of water so we can conclude that the presence of rust in the water of Westfield is the reason for the change in colour.
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