McMillan Park Reservoir Historic District
The city’s first water treatment plant was both a victory for public health and a monument to the City Beautiful movement.
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Constructed over a period of decades at the turn of the 20th century, the McMillan Park Reservoir’s original slow sand filtration system was DC’s first water purification facility. Connected to the Washington Aqueduct, the reservoir treated the city’s public water supply and in doing so eliminated typhoid and malaria epidemics in DC.
The McMillan Park Reservoir’s name honors Senator James McMillan of Michigan, best known for his work with the Senate Park Improvement Commission. The commission’s McMillan Plan sought to redesign the National Mall to better reflect Pierre L’Enfant’s original plan for the city. Although McMillan did not live to see the reservoir completed, his work and his collaboration with major figures of the City Beautiful movement, such as Frederick Law Olmsted Jr., Charles F. McKim, Herbert Adams, and Charles Platt are reflected in the original design of McMillan Park. This is especially true of Olmsted’s landscaping, which concealed the water treatment facility under a public park. McMillan Park remained open to and popular with the public until World War II, when it was fenced off for fear of enemies sabotaging the city’s water supply.
In the 1980s, the original filtration system was decommissioned, having become obsolete, and a new treatment facility now operates next to the old one. Debates ensued over the proposed redevelopment of much of the original McMillan Park. A plan was finally selected and the space between North Capitol and First streets NW is now in the process of being redeveloped.
In 2024, the redeveloped southern portion of the site opened as part of the new Reservoir District. Here, visitors will find the restored McMillan Memorial Fountain (which was also moved to a new location), as well as ten concrete sand bins and two regulator houses. The site also includes a new community/recreation center, playground, fountains, and public park. The Slow Sand Filtration Plant is visible as well.
The next phase of the redevelopment, on the central and northern portions of the site, will include new housing, a grocery store, restaurants and stores, and two health centers. The other concrete sand bins and regulator houses will be incorporated into the new, mixed-use development.
DC Inventory: August 21, 1991
National Register: February 20, 2013 (McMillan Park Reservoir Historic District)
