For my basement darkroom, I have a Liberty pump (libertypumps.com) under my darkroom sink which goes through a checkvalve and empties into the waste pipe which happens to be on the other side of the wall. A liberty pump is "for gray wastewater applications, the 404 is perfect for laundry tray sinks, bar sinks, washing machines and other basement remodeling projects. The system arrives fully assembled and ready to install." The scary part was cutting into the waste pipe to install a fitting into which the pump drains. The annoying part is the THUMP when the check valve closes.