Yes, they contain water from the rain, but room 2 is the only sink that has a plumbable sink to the rain barrels positioned above. And I've tried multiple positions for the sinks and rain barrels above to test whether it's a positioning issues, or a rain barrel type issue. No change to room 2 being the only room that can plumb to barrels once they have rain water.   I've not entirely sure how to check while in debug mode, since I've never explored that side of things. Any quick steps on how to do this?      

[42.7.0] [rev:28118] still actual, devs! (author, update ur title)

Are the rain barrels themselves interactable and do they already contain some water from raining? Do the two rooms at the bottom floor act like they are "interior" rooms? You can generally see that if the temperature is different outside than it is inside a room.

GREAT THANKS!   bug is still actual, devs

Version:[42.7.0] [rev:28118] Mode: [Singleplayer] Server settings: [N/A] Mods: [do not matter] Save: [do not matter] Reproduction steps: Chopping_block Surface = 13 ; is too low and clipping it should be around 18