There’s just as much activity in the caves and sewers underneath the Sword Coast as in the forests and towns on the surface. InBaldur’s Gate 3, players can see some of this variety in locations like the Underdark, Whispering Caverns, the Hag’s subterranean headquarters in Acts 1 and 3, along with a vast area encompassing the sewers of Baldur’s Gate itself.

Baldur’s Gate is one of Faerun’s major cities, with an equally vast sewer system, and even the oldBaldur’s Gategames had all kinds of disgusting, strange, and valuable mysteries hiding beneath the ordered streets. One of these mysteries inBG3is theSluice-Gate Puzzle.This puzzle not only opens up the Cistern and another access point to the surface but is required to complete a quest and recruit a legacy character.

The city in Baldur’s Gate 3

Updated June 15, 2025 by Kristy Ambrose:It’s been a year after the game’s official launch, and adventurers are still exploringthe city’s seamy underbellyand discovering the Sluice-Gate Puzzle. Even protagonists that aren’t interested in saving Minsc as part of the quest still have to confront the Stone Lord, and there’s more than one quest that leads through this gruesome gauntlet whether the main character likes it or not. For those who are new to the game, and also to returning gamers enjoying the adventure yet again, there’s more useful information about solving the Sluice-Gate Puzzle.

The City Sewers

A Detailed, Cryptic Area Filled With Secrets, Treasure, And Disgusting Goo

Players can also use the following locations to access the sewers, which is where the Sluice-Gate and Cistern are located. The complete map of the sewers underneath Baldur’s Gate includes the Lower City sewers, the Temple of Bhaal, and the Undercity Ruins, alongwith a few other locations.

There are threeWaypointsin the sewers for fast travel, one near The Temple of Bhaal, another just outside the temple’s door by the Undercity Ruins, and one more by the City Sewers that leads to a central location near the lower level of the Thieves' Den. The City Sewers is the most centrally located and is the closest to the Sluice-Gate Puzzle.

Baldurs-Gate-3-How-To-Recruit-Minsc-High-Harper-03

Not So Abandoned, In Fact It’s Rather Crowded

The Note

There’s aNote To Sanitation Workerspinned next to the Temperature Valve. It gives the player a clue as to how the puzzle can be solved. It says the water and heat have to be at “optimum” levels. This meansthe most ideal temperature, not the highest,so keep this in mind if the valves read too low or too high. This is also a time-sensitive puzzle, and the water levels will be reduced if left untouched for too long.

Turning The Valves

When the cursor moves over the valves, it turns into a small gear, allowing the player to interact with them. If the levels are wrong and the player wants to start over, there’s an Emergency Release Valve tucked next to the Temperature Valve that resets both mechanisms.

After the gate is opened, it can’t be closed again, even from the other side. It might seem inconvenient, but at leastthat makes it impossibleto get locked in the Cistern.

The counting house is labeled on the map

The Sluice Gate and the adjoining Cistern have puddles of acid and brine in various spots at ground level. Take care to avoid AoE damage from these acrid substances when the party is walking through the oversized pipe to the Cistern.

Visit The Counting House And Thieves' Guild First

Tocomplete the quest to recruit Minsc, players must open up the Sluice-Gate and gain access to the Cistern. Players also need to have Jaheira in their party and be prepared to use non-lethal combat against Minsc.

Baldur’s Gate 3 Tag Page Cover Art