WASHINGTON — DC Water officials said recent snow and rain have not worsened contamination levels linked to the Potomac sewer line failure, even as crews confront new engineering hurdles and unresolved questions about how repair costs will be divided. The agency confirmed that Mayor Muriel Bowser previously sought full federal reimbursement for the sewer collapse under disaster aid provisions. However, the U.S. Army Corps of Engineers indicated Monday that the current agreement cov