This film related to economics in many ways. People pay for the same water they could get out of their tap, by buying water out of bottles. Water is a supply and demand product, so buying bottled water only gives water companies more money to spend.
What is the bias of the film?
Yes this film is bias, it doesn't show any sympathy for water companies and makes them look like they are the "bad guys". The film does this by only showing the things water companies have done wrong, and not the things that the people who aren't involved in these companies have done wrong.