MADISON, Wis. (AP) – The state Supreme Court has ordered the Milwaukee sewage district to ensure groundwater doesn’t seep into its deep tunnel storage system.  Bostco LLC filed a lawsuit in 2003 alleging seepage into the tunnel had drawn down groundwater beneath the city’s downtown, exposing the foundation of Bostco’s buildings to air and causing them to rot.  A judge ordered the district to line the downtown portion of the tunnel with concrete, a move the district maintained could cost tens of millions of dollars. A state appeals court ruled the district didn’t have to take that step. The Supreme Court reversed that ruling Thursday and sent the case back to the circuit court level, suggesting a judge hold a hearing on the district’s abatement options.  The district’s attorneys didn’t immediately return messages.