The Decanter of Endless Water, DMG pg. 161, can fire a 30 foot long, 1 foot wide stream of water that can knock a target prone. On top of that, it keeps streaming until the end of my next turn (important).

A Vampire, MM pg. 297, takes 20 acid damage if it ends its turn in running water.

If I somehow manage to get this going on a vampire that we've prevented from moving, would this count as running water?


4 Answers 4


What Jeremy Crawford, Unofficially Says

Jeremy Crawford answered the question of what is running water. To the question:

... Is this only from natural running water, or any water that move?

Jeremy answered:

A body of running water from any source can harm a vampire.

He then clarified, when asked about water elementals:

A water elemental is a creature, not a body of running water (a stream, a river, a waterfall, or the like).


How it applies

So, based on that, If you can get enough water out of the decanter that it is stream or river like for your DM, then you're good. But even with the clarifications it is a DM call. I personally think 1 foot x 1 foot of moving water is enough to count as a body of running water.

I, personally, would give the vamp a dex save (DC 15??) to see if he can dodge it before it hits him.

  • 4
    \$\begingroup\$ They already get a Strength save against it knocking them over. \$\endgroup\$ Mar 15, 2017 at 17:34
  • 1
    \$\begingroup\$ He specifically said "body of water." This generally implies a much larger thing than a 1' x 1' thing. \$\endgroup\$ Mar 16, 2017 at 1:10
  • 5
    \$\begingroup\$ @MarcusYoder Don't forget it's 1' x 1' x 30'. I'd say a natural stream 1' wide and 1' deep would certainly count. \$\endgroup\$ Mar 16, 2017 at 7:46
  • 2
    \$\begingroup\$ He also said "from any source," and a DoEW is a source. Which is why I've accepted this answer. \$\endgroup\$ Mar 17, 2017 at 12:32
  • 2
    \$\begingroup\$ The stream may be 1 foot wide, but that doesn't make it a solid sheet of water. A geyser of water is broken up into many fast moving droplets. This is very different than a slow moving solid stream. \$\endgroup\$ Mar 17, 2017 at 16:56

I think you've exhausted the specific rules in your question, so you're going to need your DM to rule on this, or if you're a DM - decide!

  • I would certainly reward player ingenuity and allow this effect for one turn.
  • But it would also be possible to make a case for the Vampire not being "in" running water (in the same way it would be if it were in a river). Also the DM could rule that the water canon knocks it back, and out of the way of the water.

Yes, because the decanter produces running water

You've demonstrated in your question that it's mechanically possible to force the vampire to end its turn within the geyser produced by the Decanter. That geyser is running water, which means that you can force the vampire to end its turn in running water and take the ensuing damage.

In the remainder of this answer, I'll explain why the geyser is running water (redundant thought that might sound):

  • Using 'running water' as understood in common parlance (everyday speech)
  • Examining the dictionary definition of 'running' as applied to water
  • Explaining that we're not beholden to design intent/unofficial sources

Defining running water

Common Parlance

'Running water' isn't a rules term, which means we take its meaning from common parlance. 'Running water' is a very broad term which can be reasonably used to describe many kinds of moving water, such as:

  • The running water that comprises a stream
  • The running water that comes out of a bathroom tap
  • The running water that flows through a gutter
  • Any non-stagnant water

Dictionary definitions

In everyday speech, the word coupling 'running water' can serve as shorthand for natural bodies of flowing water such as rivers and streams. However, the broader definition of the term is best understood by examining the effect of the adjective 'running' on the noun 'water'.

Dictionary.com lists several definitions for running, including:

  • galloping, racing, moving, or passing rapidly.
  • flowing, as a stream

The latter definition can be presumed to be derived from the former; 'running' describes the way that water flows in a stream because 'running' describes something that is 'moving or passing rapidly'. Hence, any water which is moving or passing rapidly can be considered running water.

Ignoring design intent

Rules designer Jeremy Crawford does not agree with this ruling, and has said so in a tweet:

Running body of water =/= body of running water.

Jeremy's tweets are no longer official rules, so that doesn't matter. His interpretation of the rule is that 'running water' should be understood (as it often is) as shorthand for a '(presumably natural?) body of running water'. However the Vampire's stat block makes no mention of a 'body' of water, and only specifies that the water must be running. I've demonstrated above that this phrase has a much broader definition than select natural phenomena.


The '30 foot long, 1 foot wide stream of water' produced by a Decanter of Endless Water is running water. If you force a vampire to end its turn there, it takes 20 acid damage.

A DM might decide, based on their understanding of vampire-lore, their interpretation of 'running water' or their reverence for JC's design ideals, that only natural bodies of water count for the purposes of harming vampires. Rule 0 gives them license to do that: They're choosing a narrow adjudication when the rules support a broad one.

  • \$\begingroup\$ +1 I like this one better that the currently accepted answer. At least where I live, "running water" would be used to refer to any continous or near continuous stream of moving water... rain probably would not count but the small column conming out of a hose would (at least for a while, I might agree that it's not "running" after a certain point). \$\endgroup\$
    – Patrick87
    Jul 11, 2021 at 18:40

In general, damaging effects require an attack roll or saving throw. Since none are given in the item description, your DM may assign one or rule that this is not a damaging effect. Another important question is whether your character knows about running water and vampires.

  • \$\begingroup\$ I'm not sure why so much dogpiling on this answer. Can the next person to downvote please explain why in a comment. \$\endgroup\$ Mar 16, 2017 at 9:12
  • 4
    \$\begingroup\$ Haven't downvoted, but this answer is inaccurate as not all damaging effects require an attack roll or saving throw. As stated in the question: "A Vampire, MM pg. 297, takes 20 acid damage if it ends its turn in running water." \$\endgroup\$
    – Halaster
    Mar 16, 2017 at 9:54
  • \$\begingroup\$ The answer does not say all damaging effects. It says " in general". The OP already quoted rule from MM about vampires. The question is about using the decanter as a weapon. Interestingly, the most highly voted answer suggests a DC 15 DEX save. @LucasCordina \$\endgroup\$
    – Solanacea
    Mar 16, 2017 at 13:15
  • 2
    \$\begingroup\$ In general, players should be strongly encouraged to find bizarre ways to solve problems and destroy monsters. \$\endgroup\$
    – rosuav
    Mar 16, 2017 at 13:57
  • 1
    \$\begingroup\$ I am gonna agree with @Solanacea 's comment. The as written rules are ambiguous, so the DM should make a ruling consistent with the imagined universe and consistent with other rules. \$\endgroup\$ Mar 17, 2017 at 16:55

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .