After a video by What About it discussing water deluge systems I got to thinking about it. I remember hearing that the Russians don't use water deluge systems.
Not sure if these would be considered a reliable sources but I found something on Quora and Reddit:
On Quora: Because Cape Canaveral is at sea level, digging a deep hole for clearance would be problematic. Because Russia's cosmodrome is at a higher elevation, it's easier to dig a big hole for exhaust deflection.
On Reddit: In the harsh Russian winter, the water would freeze.
Also in the pictures for soyuz launch I don't see any water. https://en.wikipedia.org/wiki/File:Soyuz_expedition_19_launch_pad.jpg https://www.defenseworld.net/news/26790/SpaceX_Rocket_Launch_on_May_27_to_Break_Russian_Monopoly#.X0jkfchKiM0 http://www.russianspaceweb.com/kanopus-v5-v6.html
But Wikipedia says that the launch pad at the Baikonur Cosmodrome for Energia rocket had a water deluge system. Ok that's a yes for at least one Russian launch pad. https://en.wikipedia.org/wiki/Sound_suppression_system
Do the Russians use a water deluge system when launching their current rockets? I'm looking for some reliable source discussing the lack of use of water deluge systems when launching their current rockets.