When players first enter the Sluice-Gate Puzzle Room, they'll see two round valves. The one on the left is labeled Water Level Valve, and the one on the left is marked as the Water Temperature Valve.

Time your clicks when interacting with the water and temperature valves to open the sluice gate. In any case, here's how we solved the Baldur's Gate 3 Abandoned Cistern valve puzzle: Select only ...

The note reads that the valves need to be at optimal levels ... Ironically, managing to find the answer to the Sluice Gate puzzle in Baldur's Gate 3 inevitably leads to even more questions.