Fun fact: a gathering of maggots can be called a “wriggling”, a “chewing” or a “parliament” of maggots. I prefer “parliament”.
Speaking of unwelcome infestations, insects can also invade a hot tub. While doing hot tub removals, we’ve been bitten by ants and spiders, stung by wasps, and have had to scoop pounds of wriggling maggots. So be prepared to inherit bugs, eggs and larvae when buying a used hot tub from a private seller.
Although there’s a possibility that some of these pests might already exist in your backyard, you should be reluctant to introduce them to your place when bringing in a used hot tub. They can usually be exterminated if you know about them in advance, but if not, termites and boring beetles can destroy your hot tub frame/skirting, and may migrate to your home (deck, furniture, house walls, etc.), so it’s best to not have to deal with them at all.