Can a contractor file a lien against my property when he was hired to do the work by the pool company that we had signed a contract with? We have already paid the pool company and they have not paid the contractor. The contractor had threatened to file a lien against our property. Since we do not have a contract with the contractor, can they file a lien against our property?

Without a contract with you, I don't see how he could, but that doesn't mean he can't try.

Since you have gained the benefit of the work he did, there may in fact be a way around the contract specifically with you.

Hopefully someone else is looking at this and may have a better answer.

Good question. I believe they probably would have a good chance to get such a lien filed, but with the proper documentation I don't think you'd have much trouble getting it removed.

Do you have detailed documentation showing that you paid the original pool company for the work that they subbed out to this other contractor?

Is there a location that you and the contractor can show up to together to confront the pool company who's stiffing the guy? What does the pool company say about why they haven't paid the guy? I don't blame him for being mad and ready to do something - too bad his anger is mis-directed!

Yes, the subcontractor can file a mechanic's lien. You should contact the pool company immediately to find out why they haven't paid their sub. If they don't pay their sub and the sub files a lien then you will have to sue the pool company to force the payment.

Yes they can, this happens all the time. One of the reasons that there are legal papers to be used when having sub contractors.
But you as noted can go back to the pool company