Taishan Mansion is one of the domains (dungeons) in Genshin Impact.
You can unlock this domain when you reach Adventure Rank 27. However, the domain entrance is submerged in water.
Furthermore, you probably can’t swim underwater as it’s not a feature of the game.
Here’s how you can reduce the water level and unlock Taishan Mansion in Genshin Impact.
Taishan Mansion location
The domain Taishan Mansion is located in Jueyun Karst, Liyue.
How to reduce water level
The first step to reduce the water level by half is by getting to the monument on the hill.
You have to start the challenge and defeat the enemies.
There are three waves of enemies here, which includes enemies like Abyss Mages. Defeat them all and the water level will drop.
After the water level is down, it’s still not enough.
Go to the middle platform and there’s another monument.
To unlock the monument, you need to activate the three other smaller monuments around the circle.
To activate the side monuments, look for the glowing rocks / mineral deposits.
You can find the glowing rocks around the monuments, at the sides of the lake or even further outside.
Break the glowing rocks and you will have some small firefly energy following you for a short time.
Run back to one of the three monuments and the firefly will activate the monument.
Do the same thing for the other two monuments.
After all three monuments are activated, the monument in the center will also be activated and the water level drops.
The domain entrance is finally accessible and you can enter after reaching Adventure Rank 27.