Site 4 - Big Cottonwood Water Treatment Plant

  • Location:  4101 East Big Cottonwood Canyon Road

  • Date: 1957

  • Significance:  This plant processes water from Big Cottonwood Creek and delivers about 40% of the drinking water to Salt Lake City.

Photo Title: Water Treatment Plant, Big Cottonwood Canyon -Shot 1[1] 1957-1958, looking upcanyon

A water treatment plant might not seem like the most interesting site, but without its services we couldn’t live here.  The Salt Lake Valley floor sits about 4,300 feet (1,310 meters) above sea level, and the city is considered “high desert,” receiving about 15 inches of rain in a year.  Therefore, we rely heavily on water sources in our mountains.  The Big Cottonwood Creek is supplied by underground springs, dams, and snow.

The pioneers began using water from the creek soon after arrival for both drinking water and irrigating crops.  As years passed, the water system expanded from a canal built with horse-drawn plows to several large ditches.[2]  From the 1870s to the 1890s, Salt Lake and the United States experienced rapid population growth as more than 20 million people immigrated from Europe to the U.S.  The 1869 completion of the Transcontinental Railroad brought an influx of residents to Salt Lake who needed clean water.  In 1907, a conduit connected water from the canyon to Salt Lake City to support the city’s growing population of about 90,000 people.  Due to livestock grazing, mining, and lumber activity in the canyon, the upstream water became contaminated.  From 1916 to 1957, a chlorination plant operated at the mouth of the canyon.  The existing water treatment plant went online in 1957 and many improvements have been made over the years. 

Interesting Fact:  It takes about 24 hours for the water in BCC Creek to come out of your faucet in the Salt Lake Valley.

Photo Title: Looking upcanyon in 2024 - Big Cottonwood Water Treatment Plant in the foreground, the historic brick Granite Hydroelectric Power Plant (with green doors and windows) behind the water treatment plant and the winding road to Tavaci Homes in the background.[3] 

 

Photo Title: Big Cottonwood Conduit, Rocky Point looking south, P.J. Moran, May 14, 1906.[4]  Fifty years before the water treatment plant, Patrick J. Moran won the contract to build a water conduit from Big Cottonwood Canyon to Salt Lake City.  This photo is looking south from the present-day site near the Mt. Olympus trailhead showing Pete’s Rock (originally called Rocky Point) and the undeveloped valley in the background.


[1] Photo taken by Salt Lake Tribune staff, Water Treatment Plant, Big Cottonwood Canyon -Shot 1,1957-08.  J. Willard Marriott Digital Library, The University of Utah, Salt Lake City. MSS C 400 Salt Lake Tribune Negative Collection, ark:/87278/s69p5kfz. Accessed August 16, 2025.

[2] Roberts, Allen D.  City Between the Canyons, A History of Cottonwood Heights, 1849-1953. Cottonwood Heights, City of Cottonwood Heights, 2018, p.161.

[3] Johnson, Max. Big Cottonwood Canyon Water Treatment Plant.  December 17, 2024.  Photograph. Big Cottonwood Canyon Historical Society, Brighton, UT.

[4] Shipler Commercial Photographers. Big Cottonwood Canyon p.44.  May 14, 1906.  J Willard Marriott Digital Library, The University of Utah, Salt Lake City. Utah State Historical Society classified Photo Collection, 23025, https://collections.lib.utah.edu/ark:/87278/s6p001r0.  Accessed August 16, 2025.

Learn More:

https://sevencanyonstrust.org

https://cottonwoodcanyons.org

https://hiddenwaters.org

https://cwc.utah.gov/central-wasatch-dashboard/vegetation/watershed-history/

 

Moran, William L. “A Dam in the Desert: Pat Moran’s Last Water Venture.” Salt Lake City, Utah Historical Society, Utah Historical Quarterly, Volume 50, Number 1, 1982.