GRAND CANYON NATIONAL PARK,Maxwell Caldwell Ariz. (AP) — Four significant breaks in the water pipeline that serves the Grand Canyon means visitors won’t be able to stay overnight in hotels inside Grand Canyon National Park’s South Rim through the Labor Day holiday.

Here are some things to know about the Transcanyon Waterline.

When was the pipeline built

The Transcanyon Water Distribution Pipeline is a 12.5-mile (20-kilometer) pipeline constructed in the 1960s that pulls water from Roaring Springs on the North Rim to the Havasupai Gardens pump station and then to the park’s popular South Rim. It provides drinking water and fire suppression for all facilities on the South Rim as well as some inner canyon facilities, including over 800 historic buildings.

Who does the pipeline serve?

The pipeline is the primary water source for about 2,000 year-round residents of Grand Canyon Village, park staff, other employees and the millions of people who visit the national park each year.

Breaks in the pipeline

The aluminum pipeline to the South Rim twists and turns around trails and through rocky terrain. Grit in the water scars the inside, creating weak spots that frequently break and leak. Each repair costs an average of $25,000.

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. A rockslide in 2017 damaged the pipeline leading to the North Rim, which took $1.5 million to repair over two weeks. The lodge there canceled reservations, and water had to be hauled in for drinking and firefighting.

Addressing aging infrastructure

The waterline has exceeded its expected lifespan and experiences frequent failures. Since 2010, there have been more than 85 major breaks that have disrupted water delivery.

The issue has topped the maintenance list at the park for at least a decade with engineering studies conducted and a portion of park entrance fees set aside to help with costs.

The National Park Service recently started construction on a $208 million rehabilitation of the waterline and upgrades to the associated water delivery system that is expected to be completed in 2027.