Two pipelines that feed water from a spring deep in the canyon to storage tanks on the rim are the top priority for maintenance in the national park, said maintenance chief Tim Jarrell. The steel pipeline that runs up to the North Rim dates back to the 1930s and is subject to rock falls and freezing in the wintertime because it sits above ground. The aluminum pipeline that feeds the South Rim was laid underground in the 1960s, but grit in the water scars the inside through its twists and turns, creating weak spots. Other national parks, primarily in the eastern U.S., rely on municipal water supplies while more remote parks draw from wells or onsite water sources and have their own water treatment facilities.