Poly Tubing Poly Tubing may be installed above or below ground. Poly Tubing comes in five sizes: 1", 3/4", 1/2", 1/4", and 1/8". Made of polyethylene and used for main lines and laterals. Unlike PVC
pipe, it comes in coils for easy handling and storage, and weighs about
4 pounds per 100'. Maximum working pressure for the poly tubing is 60
PSI and maximum flow rate is 220 GPH (3.6 GPM).Not to exceed 60 PSI.