A near colorless, tasteless liquid that consists of 2 hydrogen atoms bound to 1 oxygen atom. This bond gives the liquid form of the molecule special properties, including great ability to act as a solvent and a high surface tension, allowing small animals and insects to walk on its surface in liquid form.

It seems almost pointless to defines something so ubiquitous in our lives, but I feel like its important to know where we’re starting so we can have a better idea where we’re going.

The sheer number of topics of research revolving around water are enormous. I have tried to boil those topics down to those that I think are most important in Dungeons and Dragons and present it in an bullet-point, rapid fire presentation. This is just me, doing research and presenting it. I hope it is of some use to you!

At a microscopic level

The unusual bonds of H20 molecules give it many unique properties. As water gets cooler, the liquid contracts until it reaches a temperature of 4 C just like most other liquids. As the temperature continues to decline, the water unusually expands. This expansion causes it to rise to the top and eventually freeze. This is how aquatic life in lakes can survive winters: the water on the bottom typically remains around 4 C while the colder rises to the top and freezes over.

Pure water acts as a good insulator, but most water we encounter is anything but pure. Dissolved salts in the water contain ions of sodium (Na +), Calcium (Ca 2+), Magnesium(2+), among others, which allow electrons to move freely through the substance. The more dissolved salts in the water, the more the conductivity increases. A salt body of water can have up to 1000x the conductivity of fresh water.

Roughly 2.5% of water on Earth is fresh. 98% of that amount is locked away frozen in ice caps. All in all, there is an estimated 326 million trillion gallons of water on earth. If you need all the zeros, that is 326,000,000,000,000,000,000.

The Flow of Water

Water is in constant motion, but a good starting point to begin to think about this circle is evaporation. Lakes, rivers, puddles and ponds – at the surface of all bodies of water, if the molecules can gain just enough energy, they can break off and become a gas. This vapor will enter the atmosphere where it can condense into clouds (where it will precipitate as rain and snow) or will stay closer to the ground in the form of fog or dew. Depending on where and the amount that returns to Earth, it can accumulate into a variety of forms. Some of that water can even seep into the ground, creating underground rivers and even pop back up to the surface as a spring.

What’s in a name?

Lakes, rivers, streams – all of these terms are familiar. But there are a few terms that are arguably a little spicier than those found in every day conversation. Wadi or Draw – a dry creek bed that fills during heavy rain Bay or Gulf – body of water bordered on 3 sides. Gulf is larger Basin – a region where rainfall or snow melt drains downhill into another body of water. Delta – where a river flows into the ocean or sea Fjord – a narrow inlet of sea between mountain peaks Lagoon – a comparatively shallow salt or brackish body of water separated from the deeper sea by exposed sandbank or coral Loch – another name for a body of water Rill – shallow channel of running water Seep – body of water formed by a spring Tarn – a mountain lake or pool formed in a cirque



It’s all about survival

For Dungeons and Dragons, a character needs about 1 gallon of water a day, or 2 if its hot. Each waterskin holds ½ gallon. Some games hand-wave this tracking, as it does add a bit more gritty bookkeeping to games. It’s important to know what water does to or for the body to see if it’s something you want to track in your game.

Internally, water is vital. It moves your blood through every organ, delivering oxygen and nutrients. If you blood can’t move, your body starves and suffocates. Water also removes waste products such as blood urea nitrogen (BUN) from your body in the form of urine.

After a day without it, your physical and cognitive functions start to slow. After 3 days, your body is at risk of shutting down. A Constitution check may be called for when trying to go without water for more than a day. If a character only consumes half the amount needed, the Constitution save is DC15. Any less and the character automatically fails. The consequence is one level of exhaustion (PHB 177, 185).

The DMG also states that in cases of extreme heat of temperatures >100F without access to water, a Constitution save DC 5 +1 for each hour in the heat is called for, gaining one level of exhaustion on a fail (DMG 110).

Too much water can also be a bad thing. Ingesting an excess amount of water can dilute your electrolyte balance. Your body depends on a balance of sodium, potassium and chloride ions in order for your tissues to work. Diluting those concentrations can cause serious water intoxication and can quickly become fatal.

Even if a party finds water, the quality may be sub-par. There is always a risk of catching some sort of intestinal disease, more so in stagnant bodies of water but not unheard of in running streams. Some diseases even resist chemical methods of decontamination due to cyst stages in their life cycles. Within days, symptoms appear including diarrhea, weight loss and stomach cramps and can last up to 2 months, when the body finally can fight off the infection. This can be represented with a constant level of exhaustion as well as an increased need to stay hydrated. All of this is easily fixed with magic in Dungeons and Dragons as Purify Food and Drink is a 1st level ritual spell.

Externally, water poses threats to adventurers as well. Swimming can be a real challenge in dungeons, especially when the dip is unexpected. Various studies have shown that 30 – 50% of adults don’t know basic swimming skills and are seriously challenged staying afloat. Couple this with currents and/or encumbrance and swimming can instantly become a Death Save scenario. As a DM, is it important that your paladin is wearing 60 lbs of heavy armor when their boat tips over? Should there be a quick way to cut off the armor to avoid drowning?

Frigid water adds even more complexity to swimming. At temperatures around 70F, you can survive a few hours to a couple days, depending. At 50F, you get a few hours. At 35F, you can expect an hour or less. The predicted survival time for someone treading in 50F water is 2 hours.

Traveling across a frozen surface of water can be a fast way to travel, but has its own risks. Blue-tinted ice is the safest, while milky white ice means it has undergone some degree of thaw and refreeze that could have introduced weaknesses. Dark ice is usually the thinnest and most likely to give way.

At temperatures >90F, a person experiences increased sweating causes you to dehydrate at a faster rate. Most hot-water heaters are recommended MAXIMUM 120F to prevent scalding. Exposure to water at that temperature for just a couple seconds causes third degree burns. Hot springs in Dungeons and Dragons could be a nice way to spend some downtime, but those that are close to thermal vents could cause just as many problems as a pool of lava.

Finding a water source typically will require a Wisdom (Survival) skill check. Some backgrounds eliminate this check altogether. It can be important sometimes to separate player knowledge and character knowledge, and this can be one of those times. If a player states that their character is “being aware of bug swarms and tracks that could lead water”, it may be handled as a Survival check. Though the player knows how to survive in the wild, the characters may not know this, or the DM may want circumstance / chance to push the story in a different direction.

These are some interesting ways survivalists find water in the wild. These phrases and descriptions could be useful in the DM’s toolbox. notices a downward slope in the terrain where water could be heading observes insect swarms notices bird flight paths at dawn or dusk find game tracks notices a patch of green vegetation at a distance in an arid environment listen for frogs

Even more obscure ways to find water following an ant trail into a tree where water may be pooling finding a small puddle in the Y branches of a tree



Water is an important factor in Dungeons and Dragons. Whether you’re crossing it or looking for a fresh source to consume, it could come with interesting choice for players to make. As a DM, we should be prepared (as much we can) to come up with the narrative after a player interacts with our world.

Hopefully this post is inspiring to you in your world building, and it allows you to confidently set the DC when that one player asks “So, can I swim across this river to get to the boat? In my chain shirt? Carrying all of my gear across 3 bags?”

If there is anything you’d like to see, or just want to leave a comment, feel free below. I hope to do a lot of these, but they are time consuming so I’m not sure at the pace I can keep up with.

Thanks for reading!