What they aren't saying is why Flint switched its supply: the Detroit system drastically raised its fees to Flint (the switch saved $19 million over the first 8 years alone), and Flint was broke as it is. The city council vote to switch was 7-1, with 6 Democrats voting "yes".
http://www.mlive.com/news/flint/index.ssf/2013/03/flint_city...
Many articles try to imply that the lead came from the new water supplier; in fact, it leached from lead pipes the existing system used as its water mains.
Yes, despite all these years of knowing the dangers of lead, neither Flint nor Detroit made any attempt to clear lead from their water delivery systems, and EPA rules allowed testing to be based on long periods of letting taps run to clear as many contaminants as possible first.
And switching back to Detroit water doesn't solve the lead problem in the mains, although it may be less acute.