Uh… yeah, they get washed. Not frequently enough for this to be wrong, but still, they do get washed.
There are specialized machines for this that resemble industrial vacuum cleaners but even bigger. Cleaned balls are bagged and get poured back once the floor and walls are sanitized. Do the operators keep track of when this was last done? Yes, and they aren’t proud of it so you won’t see cleaning logs hanging nearby like at most mall toilets.
They do get washed. Not enough, but they do.
Speaking as a parent with a horrible experience involving rotavirus:
NEVER, under ANY circumstances should you allow your kid into a ball pit. Just fucking don’t, they are gross and your whole family will puke and shit for days.
Let me guess, youre not vaccinated and nor are your kids?
Rotaviruses cannot be killed by normal sanitizing and nearly all children will have it (and developed resistance) by the age of 5. It almost never affects adults.
Might as well not let your kids do anything at that point, ballpits are not better at spreading rotaviruses than anything else. Ballpits are not clean, but the toys, floors and walls at the daycare aren’t either, not as far as rota is concerned at least
We all have every vaccine you can get. It’s possible I’m misremembering exactly what disease it was, but I promise you that a single instance of our kid in a ball pit ruined a vacation for two families.
Ballpits encourage contact with eyes, mouth, and nose, then spread it all around over the balls. They are especially difficult to clean. It would be difficult to design a better disease transmission vector if you were trying.
Also, pee is stored in the balls. It’s a scientific fact.