Although sap is still collected by some maple producers in buckets or plastic bags, the majority of maple sap is currently collected using plastic spouts and a network of tubing lines. The standard tubing used for the lines that run from tree to tree is 5/16â€ (inside diameter). Typically, 5â€20 taps are connected together using this tubing to form a lateral line, which, is then connected into larger diameter tubing called mainline. These mainlines run downhill into storage tanks where sap accumulates for later processing into maple syrup. Sometimes itâ€™s good to think of a tubing system as a watershed; with the lateral lines being the small streams and the mainlines being increasingly larger rivers.