PHILADELPHIA - A failed pumping station has prompted Philadelphia water officials to place thousands of homes in one section of the city under a boil water advisory.Approximately 18,000 customers in upper West Philadelphia have been urged to boil their water before drinking, cooking, making ice, brushing teeth, washing dishes and preparing formula.The advisory began Sunday after a pumping station failed, and is impacting the following areas until further notice:Water pressure has since been restored, but officials say residents should still boil their water."A lack of pressure can create a vacuum that could pull disease-causing organisms such as bacteria into water pipes," they said.To ensure water is safe, affected households should:For more information, or to check a map of the affected areas, visits the Philadelphia Water site. .