When designing plumbing, what is the most efficient way to pump water to a roof?
Head is a term used to identify the vertical distance between the pump output and terminus. This is where we figure out how hard the pump has to fight gravity. Another thing to remember is the rule of thumb is every 90 degree elbow is equal to 20 feet or 6m of pipe. How much water you want to move and your head distance will determine pump and discharge pipe diameter. So we need to know head distance, volume in lpm or m^3/hr to get an idea of where to start. And FYI, even though gravity will help the water fall, you will need a bigger motor to start against the head pressure meaning a bigger pump than you really need. Go horizontal.