ETA
One of the people that I was a nanny for WAS a CPA and they never held out a penny of taxes or SS on me, they filed my wages at the end of the year on their taxes for the child care benefit. They went by the law. They didn't owe taxes on me because I was not employed by a business, I was babysitting, not an employee.
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They are technically just a babysitter. If they live in and receive other compensation then I'd say you should pay taxes on them.
They are contract labor, they work for you and they are responsible for paying their own taxes. Do you pay taxes on what you pay a plumber? No, of course not. Do you pay taxes on a lawn boy or a pool boy? They may come and do their work every week and earn a lot of money from you each year. They do NOT get taxes paid on them because they are a contract laborer. They have a particular job, they come do that job, then they get paid. They pay their own taxes on their own income.
You can claim your money you pay to them for child care with your checks even without their ss #. That's how my clients did it if they didn't get a letter from me stating what moneys they paid me during the year.
I didn't get asked very often for a letter. The parents just filed on their own checks.
I was a nanny for years. I also worked in formal child care and actually owned a child care center. As an owner I had a federal tax id number and hired people to work in a business, one that paid taxes, had insurance, had a federal tax id and state tax stuff, I was a business hiring an employee. I did also have those substitutes who I hired to do some hours. I did not take out taxes on those employees. If I had taken out SS and Federal income taxes then I would be matching those funds as required by law. Since I was paying them a flat rate I did not hold out taxes.
I think the only one who can answer this question legally is your CPA. I would not be surprised to hear that they said this person is not a taxable person.
And if you think this is not right then next time you have a mechanic fix your car be sure and tell them you're holding out taxes for them on their pay, or the roofer, they won't like it that you're doing their accounting for them. They are running their own business just like a nanny is running her own business.