ShutterstockIn August, the $400 Nebia shower got people — including Apple CEO Tim Cook — excited with its promise to use 70 percent less water than your average shower head. That’s incredibly impressive, but Hamwells says its e-Shower beats that by 20 percent. While the Nebia uses aerospace-grade spray nozzles that atomize water, allowing for a smaller volume of H2O to get you just as wet, the e-Shower recycles what normally goes down the drain.…