In 2000, the movie “Erin Brockovich” helped put the small town of Hinkley, California, on the map. The movie stars Julia Roberts as a determined law clerk who takes on the massive utility company Pacific Gas & Electric, which had been dumping chromium-6, the dangerous chemical, in Hinkley's groundwater. Brockovich is depicted gathering evidence and building a legal case against the utility. And she prevails: The movie concludes with a landmark settlement awarded to residents. But that Hollywood ending isn’t the whole story. Many residents say the settlement didn’t go far to cover mounting medical bills and moving costs. And the chromium-6 cleanup proved to be slow. It was stymied by the difficulty of containing widespread contamination and a small local water board lacking the power to enforce stricter standards. Today, Hinkley is a ghost town, and the water there is still contaminated with chromium-6.On the 50th anniversary of the Safe Drinking Water Act, investigative reporter Silvia Foster-Frau has traveled the country reporting on where America has fallen short in its promise of providing clean drinking water. In the final installment in this series, she returns to Hinkley to learn why, even with a massive spotlight, it can be so hard to clean up toxic tap water.Today’s show was produced by Emma Talkoff. It was edited by Monica Campbell and mixed by Sam Bair.Subscribe to The Washington Post here.