The property owner does not have to be notified in order to file the lien, although most states will require that constructive notice be given to the property homeowner in writing that a lien is being placed on their home. In most cases, even when the contractor has been paid, there may still be remaining, unpaid liens filed by the subcontractors who have not been paid by the general contractor in charge of the project (see Full property/owner lien report) https://www.ustitlerecords.com/product/full-property-owner-lien-report/.