Bag of Holding submerged in water

[Lupine]

Hey all, I created an item that is kind of like gunpowder mixed with sodium metal: highly explosive, and detonates when it comes into contact with water. (Not really of concern)
Anyway, the PC who is holding onto the item has a bag of holding, and is likely holding the item there. If the PC were to go swimming, would he have to worry about the water entering the bag of holding, and possibly detonating?

[Mellack]

Considering the description talks about how long creatures inside can breathe, it seems to be airtight.

[HappyDaze]

I always thought that the bag does not open on its own; it must be opened by someone. I don't think this is a rule though.

However, if the bag is opened underwater, it will be immediately destroyed! Why? Because water will rush in and fill its volume (64 cubic feet). That water will weigh almost 4,000 lbs. and anything over 500 lbs. will cause the bad to rupture.

[Demonslayer666]

I would say that the bag would not take in any water while swimming, unless you purposely opened it under water where the water could flow into it.

[Lupine]

However, if the bag is opened underwater, it will be immediately destroyed! Why? Because water will rush in and fill its volume (64 cubic feet). That water will weigh almost 4,000 lbs. and anything over 500 lbs. will cause the bad to rupture.

Wouldn't the bag just take 500 pounds of water?

[ProsecutorGodot]

Wouldn't the bag just take 500 pounds of water?

overfilling the bag is an option:

If the bag is overloaded, pierced, or torn, it ruptures and is destroyed, and its contents are scattered in the Astral Plane.

You really probably don't want to open it underwater. I'd be a bit upset with a DM who would start playing "gotcha" with a players bag who was simply submerged in water, but opening it underwater willingly leads to a natural conclusion that the water can flow in.

[AvvyR]

Considering the description talks about how long creatures inside can breathe, it seems to be airtight.

I have to agree with this. Even though the bag's description makes it seem like it's just a heavy messenger bag that's larger on the inside, the fact that air cannot flow into the space while it's closed indicates other fluids like water cannot enter a closed bag either.

[HappyDaze]

I have to agree with this. Even though the bag's description makes it seem like it's just a heavy messenger bag that's larger on the inside, the fact that air cannot flow into the space while it's closed indicates other fluids like water cannot enter a closed bag either.

It is very obviously a ziploc bag of holding.

[HappyDaze]

Wouldn't the bag just take 500 pounds of water?

Water doesn't care about the bag's silly weight limit; as a liquid, it just wants to fill available volume. In this case, doing so will overload the bag leading it to rupture.