In the UK these are called sluice valves, and they are very common in order to isolate parts of the network for maintenance. Well, they are probably called slu

In the UK these are called sluice valves, and they are very common in order to isolate parts of the network for maintenance. Well, they are probably called sluice valves in lots of other places, but the UK specific thing is the signage. Keep your eyes peeled for telltale SV signs (shown here alongside a fire hydrant indicator): https://c8.alamy.com/comp/DA5TFN/fire-hydrant-water-locator-signage-and-sluice-valve-indicators-on-DA5TFN.jpg https://c8.alamy.com/comp/DA5TFN/fire-hydrant-water-locator-...