Activist and author Erin Brockovich on her new book, "Superman's Not Coming"

It's been 20 years since the release of the film "Erin Brockovich" starring Julia Roberts, which questioned the safety of drinking water. First on “CBS This Morning,” the real Erin Brockovich discusses her career fighting for Americans and a cleaner environment in her new book, "Superman's Not Coming: Our National Water Crisis and What We The People Can Do About It."