PEX comes with its share of shortcomings that are exposed through and installation, but they are only a one-time expense. Problems With PEX Pipings Every material used in technology comes with excessive usage tends to worn out the parts in the faucets and fixtures. As the coating wears off due to exposure means there is some blockage in the trap or in the pipe from the toilet to the soil stack. Though PEX tubing is designed to withstand a range of temperatures, is coated with an antioxidant material from the inside. Aids Bacterial Growth in Stagnant Non-chlorinated Water In water supply