Image credit: Johanhilge / Wikimedia Commons · CC BY-SA 4.0 · 2018-10-31 ↗
Claremont Square: The Garden That Is Really a Water Reservoir
Pentonville / Angel · Clerkenwell → Angel → Rosebery Avenue → Great Ormond Street → Holborn · Water infrastructure / hidden engineering / Georgian square
Story
Today, visitors to Claremont Square encounter a serene Georgian square dominated by a substantial central mound, grass-covered and dotted with trees, rising unexpectedly above street level. This feature, seemingly an ornamental garden, is in fact the cleverly disguised lid of a gigantic Victorian water reservoir, a silent testament to how engineering shaped London's urban landscape and saved countless lives. This site has been crucial for the capital's water supply long before its current incarnation. As early as 1709, the New River Company, which had brought fresh drinking water to London from Hertfordshire via an artificial channel in the early 17th century, constructed an open reservoir here, known as the Upper Pond. Its elevated location was strategic: it allowed water to flow by gravity and with sufficient pressure to the lower districts of the city, facilitating its distribution through an expanding network of pipes. The reservoir's current appearance is a direct result of one of London's greatest public health crises. Following devastating cholera epidemics, particularly that of 1846, and the enactment of the 1852 Metropolitan Water Act, it became imperative to cover all urban reservoirs to protect water from atmospheric contamination and disease. It was then, in 1855, under the direction of engineer John Murray, that the old open pond was transformed into the covered reservoir now hidden beneath the mound. This monumental engineering effort not only responded to an urgent sanitary need but also elegantly integrated the infrastructure into the developing residential surroundings, creating the square's curious topography. The elegant Georgian buildings that frame it, constructed throughout the 18th and early 19th centuries, adapted to this central feature, forming a harmonious yet deceptive ensemble. Although access to the fenced enclosure remains forbidden, as it continues to be vital infrastructure, the outline of the mound and the stone parapet crowning it invite contemplation of the sheer volume of water lying beneath. The presence of this hydraulic colossus beneath an urban garden underscores how functionality and aesthetics intertwined in the Victorian era to solve monumental challenges, and how, even today, essential aspects of London life unfold discreetly beneath our feet.
What to look for
Look for the central, grass-covered mound, rising approximately four metres. Note the surrounding parapet and how the Georgian houses frame this unusual piece of water infrastructure.
Secret detail
Beneath the surface of this 'garden' lies the successor to a reservoir that, since 1709, has been an integral part of the New River Company's water supply network for London.
Where exactly
Walk around Claremont Square on the public pavement; the reservoir occupies the entire raised, fenced central enclosure in the middle of the square.
Orientation
View it from several sides of the square; there is no visitor access to the central enclosure. The best view is from the south corner.
Why it matters
This place illustrates how public health and engineering shaped London's urban landscape. It's a tangible example of a residential square adapting to integrate vital infrastructure in the wake of major Victorian epidemics.
Access & opening
Visible from surrounding public streets at all times; do not enter the fenced reservoir.
Free exterior view.
Visible anytime
Accessibility
Level public pavements around the square; gradients and crossings vary.