To drain water in SubCargo on Roblox, the usual practical answer is: you generally can’t “empty” Roblox water everywhere the way you might in a normal game, so players typically work around it by separating the submarine interior from the outside water. In Roblox-building discussions, the common advice is to remove water manually only if the sub is stationary, or to fake a dry interior with teleports, cloned interiors, or terrain edits rather than trying to make moving water fully disappear.

What usually works

  • If the sub stays in one place: use the terrain editor’s subtract/remove tools to clear water from the interior area.
  • If the sub moves: make the inside a separate dry room and teleport players into it when they enter the sub.
  • For a seamless effect: keep a “real” underwater version outside and a dry mirrored interior for players, so it looks like the sub is underwater without actually flooding the play space.

Why this is the usual solution

Roblox terrain water is not always practical to “drain” dynamically inside a moving vehicle, so builders often fake the experience instead of fighting the water system directly. That is why you’ll see suggestions like interior teleporting, forced third-person driving, or separate cloned spaces in Roblox dev discussions.

Quick setup idea

  1. Build the submarine interior as a dry room.
  2. Add an entrance trigger.
  3. Teleport players to the dry interior when they enter.
  4. Teleport them back out when they leave.
  5. Keep the outside model and water visuals for the underwater look.

If you mean a specific SubCargo mechanic or bug, the exact fix depends on whether you’re trying to drain a stationary area, a moving submarine, or a flooded room inside the ship.