Located in a 4,300sq m site at Bishop Hill in Shek Kip Mei, Sham Shui Po, the Romanesque cistern featuring underground chambers with 100 brick pillars and water pipes was discovered on December 28, 2020, while the Water Supplies Department was clearing the site in preparation to hand over to the Lands Department for other use. Reservoirs in Hong Kong were built after World War II, but the Bishop Hill cistern shows a water pipe with '1909' written on it which dates the site during the pre-war period.
Appeals for its preservation has led the Antiquities Advisory Board to examine the area and eventually declare the underground reservoir a Grade 1 historic building on March 11, 2021. A long-term preservation plan for the reservoir is still underway, but to give a glimpse of the site and allow the public to view the area, the Water Supplies Department (WSD) has launched a virtual tour that anyone can access from their computers or mobile phones. From December 2021, the premises started allowing visitors to view the site.