English to Italian Medical Medical: Dentistry user manual for a scaler

appearing twice in:
"During boil-water ***advisories***, this product should not be operated as an open water system (e.g. connected to a public water system). Dental hygiene care provider should discontinue use on patients and contact the local water authority to determine when it is safe to continue use of this product. When the ***advisory*** is cancelled, the local water authority should provide guidance for flushing of waterlines. All incoming waterlines from the public water system inside the dental office (e.g., faucets, waterlines, and dental equipment) should be flushed in accordance with manufacturer’s instructions for a period of 2 to 5 minutes."

These are instructions for connecting an ultrasonic scaler (to remove plaque) to the water system. I cannot quite grasp the meaning of advisorry in this context, particularly the second one.

TIA