Potty

In The Sims series, potty refers to a skill that is associated with a toddler's ability to relieve his/her bladder motive through the use of a potty chair. The skill first appeared with the introduction of toddlers in The Sims 2. It also appears in The Sims 3, and was introduced into The Sims 4 when the toddler patch was added on January 12, 2017.

Without sufficient potty skills, toddlers will still relieve their bladder motive with a diaper, but this will significantly reduce their hygiene motive. However, having aged up with an incompletely learned or low potty skill does not affect a child Sim's ability to relieve his/her bladder motive with a standard toilet.

The Sims 3
Potty training is one of three toddler skills. Player can buy a potty chair and the adult Sims can start teaching. Each time the toddler learns to potty, it will relieve his/her bladder and learns a quarter of the skill. After each training session, the chair will be dirty and gives bad moodlet to Sims nearby until get cleaned.

A potty trained toddler can go potty by himself. Use the potty chair interaction is now unlocked and the toddler can now use the potty chair automatically or directly by the player.

The Sims 4
Unlike other toddler skills in The Sims 4, the maximum level a toddler can attain in the potty skill is 3, and it has no corresponding child skill.

At level 1 and below, toddlers are unable to use the potty chair by themselves and will always need the supervision of a teen or older Sim. The exception is if the toddler has the independent trait.

Players can choose from two potty chairs to help train their toddlers in their potty skills: the Practice Potty (§75) and the Monster Potty Partner (§125). A potty chair will need to be cleaned from time to time, otherwise other Sims may become uncomfortable while around it.

As a toddler's potty skill level increases, they gain more abilities aimed at helping them use the potty chair more effectively and confidently:
 * Level 2: toddlers can now use the potty chair unsupervised, however the toddler will not always automatically use the potty chair when their bladder motive is low. There is still a risk that the toddler may use their diapers instead causing a low hygiene motive for them and an uncomfortable moodlet to Sims around them. The player will more often than not need to direct the toddler to the potty chair.
 * Level 3: toddlers are now more likely to automatically head for the potty chair whenever their bladder motives are low. They will also wake up from sleep in order to use the potty as opposed to their diaper. While the potty will be preferred, toddlers can still use their diapers.