A hydrostatic test is a way in which pressure vessels such as pipelines, gas cylinders, and fuel tanks can be tested for strength and leaks. The test involves filling the vessel or pipe system with a liquid, usually water, which may be dyed to aid in visual leak detection, and pressurization of the vessel to the specified test pressure. Pressure tightness can be tested by shutting off the supply valve and observing whether there is a pressure loss. The location of a leak can be visually identified more easily if the water contains a colorant.

Non-destructive testing (NDT) is the process of inspecting, testing, or evaluating materials, components or assemblies for discontinuities, or differences in characteristics without destroying the serviceability of the part or system.

CNG Cylinders Hydro Testing which is also known as Hydrostatic Testing is a non-destructive test procedure to examine cylinders for leaks, structural flaws, durability, and corrosion. As per the Indian Standards (IS) 8451:2009 & Gas Cylinder Rules,2004, it is mandatory for all CNG vehicles & Cascades to get Hydrotested every three years.