Such release and discharge, when filed for record and recorded in the office of the county recorder of the county in which such tract, lot or parcel of land is situate, shall operate as a release and discharge of the land therein described from the payment of all existing indebtedness of said district, and release the same from the lien thereof, created by the assessment roll of said district, confirmed by the court; save and except levies made or to be made for the operation and maintenance of said district.