Baldur’s Gate 3: How to Solve the Sluice Gate Puzzle in the Abandoned Cistern (BG3)

Wandering around in the City Sewers in Baldur’s Gate 3, there’s a good chance you’ll encounter the Sluice Gate Puzzle by the Abandoned Cistern. Here’s how to solve it and what it unlocks.

Where is the Abandoned Cistern?

The Abandoned Cistern and it’s associated valve puzzle is located under the Lower City in BG3’s Act 3, as far west as you can get in the City Sewers. The quickest way to get there is to use the City Sewers waypoint (which you can access via the manhole in an alleyway near Bloomridge Park), and then follow the sewers up and to the left.

You’ll know you’re in the right place when you see a large pipe you can jump onto and a handful of cultist enemies. One of them will summon several crows to attack you.

The sluice gate puzzle and its enigmatic valves found here, all the way at the end of the sewers, will lower the sewer waters directly below the valves once completed. This will give you access to the Abandoned Cistern itself. If you’re following Jaheira’s High Harper questline, you’ll want to come here after investigating the Counting House.

After Minsc’s heist in the Counting House vault, he will make his way to the Abandonded Cistern with his doppelganger crew. And who else should be there but the halfling trader who’s very happy to take the goods off of him.

But to get to them, you’ll need to solve the Sewer Valve puzzle. And it’s easier than you might think.

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How to Solve the Sewer Valve Puzzle in Baldur’s Gate 3

The goal of the Abandoned Cistern’s sewer valve puzzle is to balance the heat and amount of water. To solve the Sluice Gate / Valve puzzle in the Abandoned Cistern, you must:

• Interact with the Water Valve on the left.
• When the Water Valve status reaches “Perfect Water Level” interact with the Heat Valve.

• When the Heat Valve reaches “Perfect Warmth” the sluice gate will automatically open.

Essentially, it’s a timed puzzle. Once you interact with the water valve, it will begin flooding. Then its water pressure will drop until it hits “Perfect”, as denoted by its status condition beneath its name at the top of the screen.

You’ll then have to interact with the Heat Valve, which will start off too hot and then begin to cool until it’s “Perfect”.

Nothing else needs to be done, and the timer is very generous. But if you do mess things up, there will be an explosion which will do some fire damage and set the floor on fire. To reset the puzzle, use the valve at the far right.

Now that that’s done and the Abandoned Cistern open, you’re mere meters away from fighting Minsc. But when you’ve finally topped him, you might be wondering; Should you kill him? Save him? Or leave him to the tadpole parasite?