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Historical Timeline

Long before the city of Denver was established, the South Platte River and Cherry Creek were oases for people who traveled the dry Great Plains. These early travelers could do without many things, but not water. That's why pioneers, and the American Indians before them, camped along the banks of Cherry Creek and the South Platte River. The first residents of the area drank water directly from the creek and river. Surface wells and buckets of water sufficed for a while as a delivery system, but they soon proved inadequate. Irrigation ditches were the next step forward.

Soon, water companies began offering service to settlers. By the late 1800s, several water companies had fought, collapsed or merged. In 1918, Denver residents voted to buy the Denver Union Water Company and form the municipal agency now known as Denver Water. In doing so, voters created an entity that would operate independently from city government, thereby keeping water service separate from local politics.

Today, Denver Water is the largest and oldest water utility in the state. Its service area covers more than 335 square miles, including the City and County of Denver and several suburban distributors. A system of reservoirs networked by tunnels and canals provides water to more than a million people. Three major treatment plants — Marston, Moffat and Foothills — maintain water quality under the watchful eye of the Denver Water Quality Control Laboratory.

Denver Water has had a remarkable history, full of engineering marvels and plenty of hard work.


  • Mid-1800s
    • 1832 — Louis Vasquez, a St. Louis fur trader, built a cottonwood log fort near the confluence of the South Platte River and Clear Creek, originally called Vasquez Creek in his honor. In 1958, an important piece of infrastructure would bear his name.
    • 1858 — Discovery of gold along Platte River brought influx of white settlers. The William “Green” Russell party founded the city of Auraria on the west side of Cherry Creek. Claim jumper General William Larimer, Jr. founded the precursor to the city of Denver on the east side of Cherry Creek. Denver was part of Arapahoe County in Kansas Territory.
    • 1859 — Auraria & Cherry Creek Water Company incorporated.
    • 1860 — Capitol Hydraulic Company, which later became the Platte Water Company, was organized.

      Capitol Hydraulic Company began building City Ditch to irrigate dry landscape.

      The city of Denver absorbed Auraria in a moonlight ceremony on Larimer Street bridge over Cherry Creek.
    • 1861 — City of Denver incorporated. Its population was more than 2,600 residents.
    • 1867 — City Ditch (sometimes called Platte Water Ditch) was completed, connecting the South Platte in the Littleton area to Capitol Hill.
    • 1869 — Smith’s Lake was created with water from City Ditch. It later became North Lake in Washington Park.
    • James Archer was the president of Denver City Water Company. Click image to enlarge (ID# 12.21.7-213). 1870 — The city of Denver granted Denver City Water Company a 20-year exclusive franchise. The president was James Archer and the treasurer was David Moffat, who both figured prominently in Denver water history. The company was later absorbed into the Denver Union Water Company.

      Denver continued to see population growth with about 5,000 residents.
    • 1871 — The city’s first water plant was installed, and water supply was taken from a large well on the riverbank through a pumping station at 15th (then F Street) and Bassett streets.
    • 1872 — With a large well, a steam pump and four miles of mains, Denver City Water Company began to provide water to homes. Contracts and companies came and went, with concerns about hydrant pressure turning up in the editorial pages of the papers.
    • 1875 — Denver acquired City Ditch from Platte Water Company.
    • 1878 — Denver City Irrigation & Water Company was incorporated in an attempt to provide Denver more water for the growing population by developing supply farther up the Platte River. It was later absorbed into Denver Union Water Company. Trustees included James Archer, Walter Cheesman and David Moffat. The company started work on Lake Archer, which has since been drained, and the West Side facility, both near the current site of Denver Water’s administration building.
  • Late 1800s
    • Employees work in Denver Union Water Company's lab in this 1896 photo. Click image to enlarge (ID# 16.43.11). 1880 — Denver Water Supply Company created. Denver had approximately 35,000 residents.
    • 1882 — Denver Water Supply Company, later absorbed into Denver Union Water Company, consolidated Denver City Irrigation & Water Company and Denver City Water Company to raise enough revenue for further plant development.
    • 1883 — High Line Canal was built to irrigate thousands of acres of farmland south and east of Denver.
    • 1884 — The West Side conduit was constructed from Mississippi Street to the West Side facility, and the first galleries installed. West Denver Reservoir was completed, and the 15th Street plant shut down under the impression that the West Side facility, which is where Denver Water’s administration building is currently located, would supply all water needs for the city.
    • 1886 — The first water treatment system was installed on Cherry Creek.

      Beaver Brook Water Company was created to supply water to the town of Highlands. Beaver Brook was later absorbed into Denver Union Water Company.
    • 1887 — First Cherry Creek pipeline and small Capitol Hill reservoir completed. It brought water supply to the upper part of town and extended the distribution system toward Capitol Hill.

      Beaver Brook Water Company began installing a water system in the town of Highlands.
    • 1889 — Platte Canyon Filtration Plant, nestled high in the foothills and later named Kassler, was added to system.

      Citizens Water Company incorporated. It was later absorbed into Denver Union Water Company. The company was led by Charles Allen, George Clayton, Erastus Hallack, Richard Holme, George Kassler, William Mills and David Moffat. The company began construction of its works, beginning with infiltration galleries at Platte Canyon and Ashland Avenue Reservoir.

      The 15th Street plant reopened and a pipeline was built from the West Side facility’s reservoir to the 15th Street plant to furnish water supply.
    • 1890 — Denver Water Company, Denver City Irrigation and Water Company, Mountain Water Company, and Beaver Brook Water Company all merged into Denver City Water Works Company, which was later absorbed into Denver Union Water Company.

      Kassler underground infiltration galleries built.

      Denver’s population reached more than 106,000 residents.
    • 1892 — After two decades of several water companies fighting, collapsing or merging, the battle between two major water companies became so fierce that the Citizens Water Company, hoping to drive the American Water Works Company of New Jersey out of business, culminated a price-cutting war by offering free water. The Citizens Water Company eventually drove its competitor under.
    • 1893 — Citizens Water Company began Marston Lake, Marston Lake mechanical filter, Bear Creek water use (conveyed through Harriman Ditch), and discovered the site of the future Cheesman Reservoir.
    • 1894 — The Denver Union Water Company, which was organized by Walter Cheesman, David Moffat, George Clayton, Thomas Hayden, Moses Hallet, Erastus Hallack and Charles Hallack, purchased the Citizens Water Company plant and the failing American Water Works Company plant. The Denver Union Water Company — predecessor of Denver Water — emerged to establish a stable system.
    • 1896 — The Denver Union Water Company built a chemical and bacteriological laboratory to safeguard public health and reduce improper taste and odor in the water. At the time, typhoid cases were increasing; after the laboratory was built, the cases decreased rapidly.
    • 1898 — Denver Union Water Company offered the city a proposition to sell the company’s entire system, including real estate.

      John Hunter, city engineer, provided $5.7 million — approximately $147 million today adjusted for inflation — to build a new plant instead of the city purchasing the Denver Union Water Company.
  • 1900s
    • Antero Reservoir was completed in 1909. Click image to enlarge (ID# 252.*.1-8766). 1902 — Marston Reservoir was completed.

      After the turn of the century, Denver’s population topped more than 130,000 residents.
    • 1903 — Construction began on Platte Canyon Reservoir; it was completed the next year.
    • 1905 — Cheesman Dam and Reservoir was completed. The reservoir, which is on the South Platte River, was hailed as the solution to Denver’s water storage problems. At the time, the dam was the world’s tallest at 221 feet and the first reservoir of Denver’s mountain storage facilities. Cheesman remains a major accomplishment and keystone for Denver’s water needs.
    • 1906 — Kassler filter beds built; it was the first slow sand filter plant located west of the Mississippi River.
    • 1909 — Antero Reservoir, located on the South Fork of the South Platte River, was completed to supplement the High Line Canal’s water supply.
  • 1910s
    • 1911 — Chlorine first used to sterilize city water supply.

      Denver’s population exceeded more than 213,000 residents.
    • 1918 — Denver residents voted to create a five-member Board of Water Commissioners and buy the Denver Union Water Company's water system for nearly $14 million — more than $209 million today adjusted for inflation — creating Denver Water.

    Employees pose in front of the Denver Union Water Company building in downtown Denver. Click image to enlarge (ID#16.27.8689).

  • 1920s
    • Marston Treatment Plant was built in 1925. Click image to enlarge (ID# 62.21.2017-A). 1921 — George Bull, with a party of engineers, began surveying places to divert water from the Fraser River and Williams Fork.

      At the time, the heaviest rainfall in recorded history destroyed four of Denver’s conduits, which meant half of Denver’s water supply had to be carried through one conduit. Residents had to conserve water while 100 men worked day and night for 48 hours to repair the pipes.

      By this time, Denver’s population exceeded more than 256,000 people.
    • 1922 — Colorado River Compact agreed upon, allotting water rights to states in upper basin (Colorado, New Mexico, Utah and Wyoming) and lower basin (Arizona, California and Nevada). The agreement was approved by all states but Arizona in 1923.

      Board started irrigation restrictions, which ended in 1937.
    • 1924 — Board of Water Commissioners took over operation of Antero Reservoir and High Line Canal, following years of litigation.
      Board bought out Denver Highlands Water Company, taking over water system for former town of Highlands.
    • 1925 — Water restrictions were put into place, limiting irrigation to two-hour blocks (morning and evening), four days per week.

      Marston Treatment Plant built.
    • 1927 — The pilot bore of the famous Moffat Railroad Tunnel was completed. Denver Water would enlarge and line this bore about a decade later to carry water from the West Slope to Denver.
    • 1928 — Water rates increased approximately 20 percent, except for irrigation.
  • 1930s
    • Employees stand outside of the field office at Eleven Mile Canyon Reservoir. Click image to enlarge (ID# 59.79.2913). 1932 — Eleven Mile Canyon Dam completed amid the worst drought in the nation’s history. At the time, it was the largest reservoir in the Denver system (currently, it’s the second largest and one of the largest bodies of water in Colorado  east of the Continental Divide).

      The city continued to see population growth. By this time, more than 287,000 people inhabited Denver.
    • 1933 — Board of Water Commissioners bought water rights in irrigation ditches above Denver and in South Park.

      A drought in 1931 and 1932 instigated widespread concern about shortage of Denver’s water supply.
    • 1935 — Construction began on Moffat Water Tunnel Diversion Project, which was part of the New Deal’s Public Works Administration program; the Moffat Tunnel was enlarged and partially lined.
    • 1936 — The first delivery of water through the Moffat Water Tunnel took place. This, during the height of the Dust Bowl drought and continuing population explosion.

      South Boulder Diversion Intake Dam completed.

      First portion of Fraser River Diversion completed.
    • 1937 — Ralston Reservoir, near Golden, finished.

      Moffat Treatment Plant opened.
    • 1938 — The original dam at Williams Fork Reservoir completed.
    • 1939 — Montclair Pump Station started service.
  • 1940s
    • Harold D. Roberts, left; August P. Gumlick, middle; and George R. Morrison, former Board president, right, go over paperwork. Click to enlarge (ID# 72.3.8348). 1940 — The first portion of Williams Fork Diversion was completed.

      August P. Gumlick Tunnel (originally called Jones Pass Tunnel) built.

      Denver had a population of more than 322,000 residents.
    • 1946 — Denver Water began construction work on the 23.3-mile Montezuma Tunnel, later to be named the Harold D. Roberts Tunnel, to carry water under the Continental Divide.
  • 1950s
    • Gross Reservoir was completed in 1954. Click image to enlarge (ID# 83.*.8-226). 1953 — Another drought struck Colorado, ending in 1957.

      Denver’s population climbed past 415,000 people.
    • 1954 — Gross Reservoir, named for Denver Water former Chief Engineer Dwight D. Gross, was completed.

      Because of the drought, water restrictions were enforced from 1954 to 1957.
    • 1955 — Montezuma Tunnel was renamed Harold D. Roberts Tunnel.
    • 1958 — Denver Water completed lining the Gumlick and Moffat tunnels.

      Vasquez Tunnel was completed.
    • 1959 — Williams Fork Reservoir was expanded and a hydroelectric generating plant was built, making it Denver Water’s first hydro plant. The original dam was built in 1938.
  • 1960s
    • The original town of Dillon had to be moved to make way for Dillon Reservoir. Click image to enlarge (ID #127.64.15-1682). 1961 — Marston Treatment Plant micro-strainer and clear water reservoir addition finished.

      The state legislature created Metro Wastewater District to provide wastewater transmission and treatment services to member municipalities and special connectors in compliance with federal, state and county laws.

      Original town of Dillon was vacated to make way for reservoir.
    • 1962 — Harold D. Roberts Tunnel completed. The tunnel, more than 23 miles in length, moves water from Dillon Reservoir to the South Platte River.
    • 1963 — Dillon Reservoir was completed, which doubled Denver’s raw water storage.
    • 1964 — New intake dams at Platte Canyon and Marston Reservoirs were finished.
    • The 1965 South Platte Flood caused extensive damage to Denver. (ID# 101.*.21) 1965 — South Platte River flooded, causing damage to Denver’s water system.
    • 1967 — Marston Treatment Plant rapid sand addition was completed.
    • 1969 — Water Quality Control Laboratory was completed.
  • 1970s
    • Denver Water's current administration building was completed in 1977. Click image to enlarge (ID# 142.47.186). 1970 — Marston’s south filter plant, which had operated since 1896, was discontinued and replaced by the north filter.
    • 1972 — Kassler Treatment Plant Reservoir and Pump Station completed.
    • 1973 — American Society of Civil Engineers designated Cheesman Dam a National Civil Engineering Landmark.
    • 1977 — Denver Water’s new administration building, at the site of an old pump station, was completed.
    • 1979 — One of the provisions of the Foothills Agreement required the creation of the Citizens Advisory Committee, which advises the Board of public concerns.
  • 1980s
    • A Denver Water employee coined the term Xeriscape. Click image to ennlarge. 1981 — A Denver Water employee coined the word “Xeriscape,” combining the word “landscape” and the Greek word “xeros” (meaning dry), to help make low-water-use landscaping an easily recognized concept. 
    • 1983 — Foothills Treatment Plant opened. The plant treats water from the South Platte River and the Roberts Tunnel for distribution in the Denver area.

      Strontia Springs Reservoir and Waterton Canyon completed as part of Foothills Project.

      Denver Water’s Xeriscape Demonstration Garden opened. More than 200 Xeriscape plant species are on display, ranging from trees to shrubs and turf. The garden demonstrates that while Colorado has a dry climate, there are water wise plants that are lush, colorful and easy to care for.

      Three Stone Buildings, a former pump station, opened as a meeting center and medical clinic for Denver Water employees, and museum.
    • 1985 — Kassler Filtration Plant, at the mouth of Waterton Canyon, ceased operations because it was unable to keep up with demand. Now the site is home to the Kassler Center, with many of the plant’s historical structures and equipment still in place.
    • 1986 — Washington Park added to the National and State Register of Historic Places, which includes a portion of City Ditch.
    • 1987 — Denver Water began converting all remaining flat rate residents to meters.
    • 1989 — The Army Corps of Engineers issued a construction permit for Two Forks Reservoir. Later that year, the Environmental Protection Agency announced it would begin the veto process for the project. Two Forks, which could have stored 1.1 million acre-feet of water, would have been built on the South Platte River about 25 miles upstream of Denver.
  • 1990s
    • By the late 1990s, snowpack readings in Denver Water’s water collection system began averaging less than normal, a quiet precursor to the 2002 drought. Click image to enlarge. 1990 — The proposed Two Forks Dam project on South Platte River was vetoed by the Environmental Protection Agency.
    • 1991 — Meters became mandatory for all customers on Jan. 1, 1991. Before that, some customers were being charged a flat rate for their water usage instead of being metered for their consumption.
    • 1992 — With the Two Forks project vetoed, Denver’s Board of Water Commissioners decided not to extend its geographic service boundaries. The Board instead decided to focus on supplying water to the growth within its existing boundaries.
    • 1995 — Denver International Airport opened. Denver Water began providing water to the airport.
    • 1996 — The Buffalo Creek Fire burned through the forest near the Upper South Platte. Sediment problems from the subsequent rainstorms still cause problems for Denver Water’s Strontia Springs Reservoir.
    • 1997 — Denver Water’s Conservation Master Plan put forth conservation strategies with cooperation of the Citizens Advisory Committee, other conservation professionals, and innovative private sector leaders.
    • 1998 — Snow pack readings in Denver Water’s water collection system began averaging less than normal, a quiet precursor to the 2002 drought.
  • 2000s
    • Denver Water's award-winning advertising campaign began in 2006. Click image to enlarge. 2000 — Hi Meadow Fire burned 11,000 acres on South Platte watershed, washing silt and fire debris into the upper end of Strontia Springs Reservoir.
    • 2002 — The 2002 drought was one of the worst in Colorado’s history, forcing Denver Water to impose mandatory watering restrictions.

      Because of the drought, Denver Water drained Antero Reservoir to prevent evaporation loss. Antero was closed for four years to recreation.

      Denver Water began cloud seeding after a 20–year hiatus.

      Hayman Fire seared through major portions of Denver Water's watershed, charring land and forest surrounding Cheesman Reservoir. The fire burned more than 137,700 acres.
    • 2004 — Denver Water’s Recycled Water Treatment Plant and Distribution System opened, which allows Denver Water to supply recycled water to several industrial and irrigation customers.
    • 2006 — Use Only What You Need advertising campaign began.
    • 2009 — Customer Care and Billing system, which changed billing from bimonthly to monthly, was implemented.

      The U.S. Army Corps of Engineers released a draft environmental impact statement for Denver Water’s Moffat Collection System Project. The project, if approved, will provide Denver Water an additional 18,000 acre-feet of supply by raising Gross Dam 125 feet.

      The first gravel pits in Denver Water’s system opened. The Downstream Reservoir Water Storage Project allows Denver Water to store and release reusable water in its system through the use of old gravel pits that have been remodeled to store water.
  • 2010s
    • Signage marks the Hamlet J. Chips Barry III Facility. Click image to enlarge. 2010 — Longtime Denver Water Manager Chips Barry was killed in an accident a few months before his retirement.
    • 2011 — Denver Water announced the Colorado River Cooperative Agreement, with the intention to have all parties sign the agreement by the end of 2011.

      In August 2011, Montclair Pump Station was renamed the Hamlet J. “Chips” Barry III Facility in honor of Chips Barry, former manager of Denver Water.
    • 2013 — A major drought, which began in 2012, swept through the region, prompting Denver Water to declare a Stage 2 drought in early 2013. But late spring brought historic amounts of snow, and September brought unusual amounts of rain and flooding. By September, Denver Water reached its peak storage for the year. That typically happens in July — and it’s never happened in September.