General Survival

Shelter and Sleeping
When making camp for the night in the wilds, there are three critical factors: how cold it is, how wet you are, and how exposed your campsite is. If any of these factors are not accounted for, you open yourself to the risk of all sorts of hazards, ranging from mere unpleasantness to potentially life-threatening diseases.

Warmth
With the exception of temperatures above 70 degrees Fahrenheit (commonly experienced only in arid climates or the hottest summer months), some additional source of warmth is required at night beyond basic adventuring clothing.

If a character sleeps with a blanket or bedroll, they suffer no ill effects; if a character sleeps next to an open campfire or other large source of heat, they will similarly suffer no ill effects. These two are the most common means of maintaining warmth at night, but there might be other ways to do so at the GM’s discretion.

Wetness
While it is quite common for adventurers to swim in lakes, wade through rivers, and dive into dungeon pools—and thus become thoroughly soaked—it can be quite dangerous to go to sleep while still wet. Characters might also become wet from traveling in the rain, interacting with exceptionally watery creatures, bathing, or other activities.

A wet creature will dry off over the course of one hour, so long as they stay dry the entire time. If that creature is near a significant source of heat, such as a campfire or stove, that time is cut in half. Likewise, there may be additional means to quickly dry off at the GM’s discretion.

Exposure
Beyond simple rain and snow, other forms of exposure, typically wind, can sap away at a character’s strength. The simplest way to avoid exposure is through shelter, which shields a party from the outdoors.

Shelter is any structure or formation that has at least three walls and a roof. The most common sources of shelter in the wilderness are tents, caves, and ruins, but there may be others, at the GM’s discretion.

Sleeping
In order to avoid ill effects while resting, characters must satisfy all three conditions: they must stay warm, they must stay dry, and they must stay sheltered. Over the course of a long rest, if a character does not satisfy any of the above conditions, they must make a DC 10 Constitution saving throw at the end of their rest or suffer a level of exhaustion.

For each additional condition a character does not satisfy, the DC increases by 5, and the character suffers an additional level of exhaustion. For example, if a character is both cold and exposed to the wind during their rest, they must make a DC 15 Constitution saving throw or suffer two levels of exhaustion. Creatures with resistance to cold damage have advantage on these saving throws; creatures within immunity to cold damage automatically succeed.

Food
A character needs one pound of food per day, and can make food last longer by subsisting on half rations. Eating half a pound of food in a day counts as half a day without food.

A character that goes a day eating less than half a pound of food must succeed on a DC 15 Constitution saving throw or suffer one level of exhaustion.

A character can survive a number of days without food equal to 3 + his or her Constitution modifier (minimum 1). If a character would suffer a 6th level of exhaustion from lack of food before they have reached this number of days, they instead remain at 5 levels of exhaustion, but automatically suffer the 6th as soon as they reach their last day.

Each day of normal eating removes one level of exhaustion.

Water
A character needs one gallon of water per day, or two gallons per day if the weather is hot, typically above 100 degrees Fahrenheit. A character who drinks only half that much water must succeed on a DC 15 Constitution saving throw or suffer one level of exhaustion at the end of the day. A character with access to even less water automatically suffers one level of exhaustion at the end of the day. If the character already has one or more levels of exhaustion, the character takes two levels in either case.

A character must split their water consumption into at least two watches; that is, they cannot drink an entire gallon at one time and nothing else.

Each day of normal drinking removes one level of exhaustion.

Cleanliness
Adventurers to the Marches are hardy folk certainly, but even still, consuming food or water found in the Marches can be dangerous. Hunted game can carry plague or maggots, fruits and vegetables may be rotted through, and water can carry foul disease. If counteractive measures are not taken, these can lay even the mightiest of adventurers low.

Unclean Water
Water encountered in the wilderness sometimes has diseases or impurities running through it, or is otherwise unsuitable for drinking. Well-water, rainwater, water from streams or rivers, and lake-water are all safe to drink.

All other sources, such as stagnant swamp water, water found in puddles or in plants, pooled water underground, or other, less savory sources, is unclean. Water can be purified through the purify food and drink spell or similar, or by being boiled for 1 minute.

If a character drinks water that has not been purified, they must make a Constitution saving throw one hour after ingestion. The DC of the saving throw is determined by the source of the water: the purer the source, the higher the likelihood that the water is clean.

Unclean Food
While rations are the classic sustenance of adventurers, many prefer a break for something less bland, or else don’t wish to be bother carrying the rations. Ordinary food, however, will eventually rot, increasing the risk of disease. Similarly, consuming certain uncooked foods also carries a chance of disease.

Generally speaking, most food rots after one week; foods like grains, tropical fruit, most vegetables, and most cooked dishes. Raw meat of all varieties rots after 24 hours, as do most dairy products. Spells such as purify food and drink will remove any spoiling and potential diseases from rotten food, but it will not restore food matter that has rotted away.

Some foods can go longer without rotting, and a few rare types of foodstuffs, like certain cheeses, do not rot at all. Furthermore, many foodstuffs can be preserved, typically either through airtight storage or heavy salting, which extends the amount of time before the food spoils. These items and effects are determined at the GM’s discretion.

If a character consumes food that is unclean, they must make a Constitution saving throw one hour after ingestion. The DC of the save is determined by the source of food: the more rotten the food is, the higher the likelihood of disease.

Creatures that have natural adaptations against food sources that would normally carry the risk of illness, such as Lizardfolk eating raw meat, automatically succeed on appropriate Constitution saving throws from eating unclean food.