FOREWORD Addendum a revises Section A3@ ??Water System Flow Diagram?? to allow the program team the flexibility to determine what needs to be included in the flow diagram to manage the risk of legionellosis in the building water systems of health care facilities. It also removes the permissive language that was previously in the standard. Note: In this addendum@ changes to the current standard are indicated in the text by underlining (for additions) and strikethrough (for deletions) unless the instructions specifically mention some other means of indicating the changes.