Online maps and automated phone calls will let water customers know when their areas have been cleared. Residents will also be instructed on how to flush their homes of any contaminated water.
About 170 people were treated and released from emergency rooms for exposure. There were 1,045 calls to a poison control center about human exposure and 65 animal-related calls, officials said.
Associated Press writers Pam Ramsey and Mitch Weiss in Charleston, W.Va., contributed to this report.