CHARLESTON, W.Va. -- West Virginia American Water on Monday began lifting the "do-not-use" water advisory issued to 300,000 of its customers on Thursday.Customers in downtown Charleston -- in areas bordered by the Elk River, the Kanawha River and the 35th St. Bridge -- were given the go-ahead on Monday afternoon to begin flushing their systems.By late Monday afternoon, Kanawha City and some areas across the Kanawha River from the neighborhood were added. South Charleston residents were also told they could flush their pipes early Monday evening. Customers in North Charleston, the West Side and along Sissonville Drive were permitted to flush their pipes Monday night.The Edgewood area was added at 6 a.m. and the Southridge/Southside area was added at 7:28 a.m. on Tuesday.An additional section of South Hills reaching past Davis Creek was added to the online map of safe areas at noon, but was then returned to the danger zone about half an hour later. Officials blamed the initial change on a miscommunication.As of early Tuesday, the advisory had been lifted for about 28,500 customers, according to the water company.The do-not-use advisory remains in effect for customers in the rest of Kanawha County, as well as Putnam, Boone, Jackson, Lincoln, Roane, Logan and Clay counties. The Culloden area of Cabell County is also still under the advisory.When areas are given the go-ahead, customers will be asked to flush their home plumbing systems, which will require at least 15 minutes of flushing faucets, state officials said at a press conference Monday afternoon.Hospitals in the Charleston area were OK'd to begin the flushing process at about 10 a.m. Monday morning.Customers served by the Lincoln County public service district have been approved to begin the flushing process, as well, according to state Homeland Security director Jimmy Gianato.Customers can see their zone's status by entering their address into the online map at www.westvirginiaamwater.com, or by calling 855-390-4569. Once the map pinpoints an address, customers can zoom out to see their home's status. The map will identify areas that can start flushing as blue, and areas where they shouldn't start yet as red.State officials warned customers to not begin the flushing process until their zone's ban is lifted to prevent overworking the water system. If people begin flushing their systems too early -- before their area is coded by blue on the online map -- it will extend recovery time, said Jeff McIntyre, president of West Virginia American Water Co.Officials previously said they did not know much about the chemical -- Crude MCHM -- from its toxicity levels to know how to test for them. Special tests were developed to track the chemical's levels.When asked why customers should have confidence in the safety of their tap water, McIntyre touted the company's filtration system, describing the water treatment plant as "top notch." After the press conference, McIntyre said he wasn't concerned about other substances that might infiltrate the company's system."We've had diesel spills and fuel spills, and this treatment process can handle those," McIntyre said. "This particular chemical was just so strong and aggressive to our system that it overwhelmed the absorptive capacity of our system."McIntyre said he hasn't yet met with his team to review historic risk assessment information. To his knowledge, the company asks for information from tenants and property owners along the Elk River every two years.U.S. Rep. Nick Rahall, D-W.Va., said after the news conference that it was too early to say if there would be any legislative changes from Congress in response to the chemical leak."My committee ... will be exercising our oversight authority, but in due time," said Rahall, the ranking Democrat on the House Transportation and Infrastructure Committee. "We want to look at what happened, how we can keep it from happening again and if, God forbid, it were to happen again, how can our response be better than it was this time?"Despite having received Freedom Industries' "Tier 2" form last year, government officials at both the state and county levels did not have a plan to address last week's spill.Randy Huffman, secretary of the state Department of Environmental Protection, said his agency is now developing a statewide chemical inventory to keep track of facilities like Freedom Industries that don't process chemicals, but rather store them."At the governor's request, we're developing some proposals as to how we're going to more properly regulate these facilities in order to minimize the risk of a spill," Huffman said.McIntyre said testing teams will continue to monitor the chemical's levels, not only in the Elk River, but also the Kanawha and Ohio rivers. The company's Huntington treatment plant is preparing for potential effects of the leak as it moves downstream, he said.Another chemical spill occurred along the Ohio River in Belpre, Ohio, last week. That spill was 120 miles upstream from the Huntington plant, according to McIntyre.Huffman said sewer and sanitary boards throughout the affected area have been made aware of the flushing and are preparing for an increase in flow through those systems.Customers with questions about septic tanks should contact their local sanitary boards or health departments with those questions, Huffman said.Those who need assistance flushing their systems are directed to call their local emergency management offices.Fourteen people were hospitalized with non-life-threatening symptoms that could be related to the chemical leak, officials said.Crude MCHM, a coal-processing chemical that is actually 4-methylcyclohexanemethanol, leaked from a Freedom Industries facility into the Elk River on Thursday morning. Residents in parts of nine counties have been advised not to drink water or use the water in any capacity except for flushing toilets and fighting fires since then.Officials said that more than 90 percent of tests show the MCHM levels are now "well below the health risk level."But a timeline for when the water will be usable is still undetermined, McIntyre said."It's hard to predict because it depends on the behavior of the people. If people don't follow the instructions ... it will go longer," he said. "It could still be days before we have the entire system cleared. It's a very large, complex system."The black licorice odor associated with the chemical may still be prevalent, but does not mean people should flush past the recommended amount, officials said.State Superintendent of Schools Jim Phares said that schools will reopen when it is confirmed that all systems are safe, and that there will be no rush to get back to class."We want to add assurances that every child, all children, will be safe when they return to school," Phares said.Restaurants in Charleston began reopening their doors to customers upon news of the end of the do-not-use water advisory Monday afternoon.Meena Anada, co-owner of Little India on East Washington Street, said she hired a contractor to flush out the restaurant's water pipes. Anada said she would still serve customers bottled water until she felt comfortable using the faucet again.An employee at Pies and Pints on Capitol Street said the restaurant was busy with customers Monday night. The restaurant flushed out its water pipes early Monday afternoon and is serving water from the faucets.At the Charleston Town Center Mall, marketing director Lisa McCracken said all restaurants but three would reopen Tuesday morning. Those three restaurants, Dairy Queen, Five Guys Burgers and Fries and Sakkio Japan, would be inspected by the Kanawha Health Department sometime Tuesday.Reach Rachel Molenda at email@example.com or 304-348-5102. Reach Mackenzie Mays at firstname.lastname@example.org or 304-348-4814.