Winterization includes shutting the water source off at the curb and at the main interior water supply. The servicer must shut off one water source when it is not possible to shut off both. Winterization also includes a complete draining of all plumbing/heating systems, pouring of adequate amounts of antifreeze into all fixture traps (e.g., sink, toilet tanks/bowls, etc.) and completing a system check, as well as anything additional required to winterize the system properly dependent upon the system type (e.g., dry, radiant, wet/steam).
For additional information please see: Property Preservation Matrix and Reference Guide, Section 5, Initial Securing and Initial Services.