SURVIVAL DIFFICULTY:
Class 1
- Safe
- Secure
- Low Entity Count

A swimming pool in Level 303.
Level 303 is the 304th level of the Backrooms. This level consists of an infinite network of interconnected steel halls containing various swimming pools.
Description
Level 303 consists of two intertwined systems, both connected and spanning over the whole level. One of the systems is a network of steel halls with pools, and the other is a network of surrounding gardens. The halls are irregularly distributed over the level and they occupy roughly the same area as the gardens. To make both systems connected, the gardens are spanned by bridges connecting the halls. It is possible to travel between these two systems freely through numerous unlocked doors. The walls splitting the systems are mostly transparent, but some of them are opaque.
The Gardens
Grassy gardens are occasional landmarks within the level, which often contain concrete paths, playground elements, some trees, and an open roof—allowing the sky to be seen from the ground. The weather is always sunny and the level exhibits an ordinary daylight cycle, though the seasons seem static. Only summer weather has been observed at this level.
There are no documented entities in the gardens but there are only a few resources to find. Due to the relative safety of the gardens, these areas host various camps built by wanderers.
The Halls
The halls contain many different rooms. The biggest rooms are the ones that host swimming pools, but there are also other supporting rooms such as stocks and passages. Pools vary in size and shape. Some pools are small and intended for kids, containing many toys and inflatables, while others are the size of racing swimming pools.
Unlike the pools in The Frontrooms, some pools are connected to a mysterious network of flooded shafts. These shafts are square in cross-section, of diameter roughly 1 meter, and paved by glazed tiles, similar to the pools. There are lamps embedded into the shaft walls, which provide enough light for humans to see and navigate in them. The purpose of these shafts is unknown, except that they serve as a hiding place for entities. It is not known whether it is one giant network of underwater shafts or there are multiple intertwined separated networks.
Level 303 is populated by pool babies. They are roughly 70 cm tall, human-like beings with translucent bodies and distorted faces, which many people see as unnerving. They do not appear to be able to harm travelers directly; their only real way of attacking is by startling unsuspecting wanderers. This is rare though, as they tend to avoid wanderers.
Pool Baby Transformation
The pool water is crystal clean. It is drinkable but it is not advised to consume it in large quantities because it has notable side effects. When you drink or swim in the pool water, it will slowly transform your body into one of a pool baby's. This process slowly reverts when you are no longer in contact with the pool water. If you stay in the halls but without touching the pool water, there is still a notable amount of pool water steam dissolved in the air, which stops the transformation process from both advancing and reverting. The gardens do not contain the pool water steam, so the process reverts there slowly.
Exiting the level does not revert the transformation immediately, it has usually the same effect as staying in the gardens, namely slow reversion of the process. An exception is similar water-themed levels such as Level 8, Level 34, Level 41, and Level 291, where the process neither advances nor reverts.
While being exposed to the pool water, the transformation into a pool baby lasts roughly two weeks. After two days, your body will be slightly translucent and you will be better at swimming than before. After 5 days, you will be able to breathe in water. After 9 days, your body will be as translucent as the body of a pool baby and you will feel no hunger or thirst. However, that does not mean that you would not need to eat at all. At this point, your body will receive energy by shrinking its size unless it has a different source. After your body shrinks to 75% of its original size, you lose your own will completely and therefore the process is irreversible. When the body shrinks to the size of roughly 70 cm, the pool baby finds a different, yet unknown, source of energy, so it stops shrinking further.
The process of transformation into a pool baby can be reverted by staying aside from the pool water. If you stay within the pool water for 5 days or more, the lack of contact with the pool water is dangerous for you and may lead to dehydration. However, it is still possible to recover by drinking a mix of pool water and ordinary water. Drinking almond water slows down the transformation into the pool baby but it also slows down the recovery process.
It is possible to keep both free will and the super-abilities by surpassing the transformation and recovery process repeatedly but it does not work for too long. There is a chance of losing free will too early and it increases while staying in the half-transformed state and not even fully recovering from the transformation seems to decrease this risk. The record of being able to use these super-abilities while not losing free will is 28 days in the entire life.
Other Properties of Pool Water
Pool water can be brought to other levels while not losing its properties. It is therefore possible to surpass the pool baby transformation almost anywhere in the backrooms, provided that enough pool water is brought there.
Pool water does not seem to affect most of the non-human entities at all, only as much as ordinary water. One exception are wretches, whose bodies are dissolved by pool water. It also applies to humans in the wretched cycle in stages 2 and 3. However, hectolitres of the pool water are needed to kill a single wretch and it lasts hours, so it is unpractical to fight.
Entities
The only entity which has been documented in Level 303 is pool babies. Most often, they swim in the system of underwater shafts, and sometimes, they come out of the swimming pools but they never leave the halls voluntarily. If they are forced to leave the halls anyway, they try to get back as soon as possible. They seem to be able to predict human behavior, so they are very hard to catch, though not impossible. Despite they seem to be clever enough not to become caught, they lack their own will. They do not speak at all, they only occasionally emit a highly-pitched sound.
Bases, Communities, and Outposts
There is a research center called Pool Research Centre set up by the M.E.G. in the year 2008. They research the properties of the pool water. They try to exploit the benefits, such as better swimming and breathing underwater, while suppressing the side effects, such as losing free will. The research was not successful yet and the M.E.G. considering disbanding this center.
Another notable base was built by The B.N.T.G., who distributed the pool water to other levels. It can be used by wanderers who were already half-transformed into a pool baby and need to drink pool water not to become dehydrated. Or it can be used to temporarily gather the aforementioned super-abilities.
Entrances And Exits
Entrances
- Find a circular clearing on Level 302. Stand exactly in the center and drink any kind of water except almond water.
Exits
- Find an elevator hidden behind a wardrobe in one of the storage rooms. This will send you to Level 302 or to Level 304.