Large-diameter pipes exemption applies when pipes are an integral part of a water supply project, excluding consumer-paid last-mile connections. The notification grants exemption for pipes used to deliver water to treatment plants and to the first storage point; an amendment introduced a diameter-based criterion to extend exemption to pipes that are an integral part of water supply projects. After amendment, pipes meeting the diameter criterion are eligible even beyond the first storage point, but consumer-paid last-mile connections are excluded as not forming part of the project.