Castle Gatehouse, Washington Aqueduct

The Castle Gatehouse sits at the entrance to Georgetown Reservoir and combines brick construction with architectural features that resemble military fortifications. The facility manages water flow through a tunnel system to McMillan Reservoir and monitors water quality using an observation pool.

The U.S. Army Corps of Engineers built this facility in 1899 as part of efforts to modernize Washington's water system. Its construction marked a turning point in the city's approach to managing its water supply infrastructure.

The building displays design elements from the U.S. Army Corps of Engineers insignia, linking military engineering traditions with public water management. This connection shows how engineering expertise shaped the city's infrastructure needs.

The site sits on the edge of Georgetown Reservoir in the Palisades and is accessible from pathways surrounding the water works. Visitors can view the exterior architecture from public paths, but should remember this is an active working facility.

Inside sits an iron sluice gate mechanism that controls water flow and allows maintenance crews to regulate Washington's water supply. This mechanism remains hidden from most visitors even though it performs essential work daily.

Location: Washington, D.C.

Inception: 1899

Architects: United States Army Corps of Engineers

Made from material: face brick

GPS coordinates: 38.91083,-77.09000

Latest update: December 12, 2025 17:40