Without digging out the legislation so paraphrasing from memory, any new instilation is held to a higher standard of water safety necessitating a closed treated water system. That was not retrospective when introduced a decade or so ago so existing attractions like CRR can remain in use, while still having to adhere to general safety standards such as the legionella guidance quoted. I don't know the detail but for example I understand Thopre got in trouble a few years back for a newly installed squirter on RR that dumped an unacceptable amount of water on riders from their open water system due to the water quality. It was just after the station if anyone remembers it, and it really did drench you in unclean water so had to be deactivated on advice. Ultimately they couldn't significantly rework CRR without creating a closed treated water system, and I would expect the restrictions and required monitoring of water quality and volumes of water reaching riders on these older open water attractions to only increase over time as risks are identified and guidance updated. Whether that will become prohibitive to operation in the future is anyones guess.