Well, there can be MAC/NTM in drinking water and ice. If you are a person with GERD (gastro esophageal reflux disorder) you could potentially aspirate this liquid into your lungs. Then you might get exposed to MAC/NTM in the lungs.
There is a professor who posts widely on some other forums, Dr Joe Falkingham, who encourages people with bronchiectasis to drink only sterilized water or bottled spring water.
Some people here follow this protocol, others are less cautious. I am in the second group, and have continued to drink filtered tap water and alcoholic beverages throughout my journey with MAC and bronchiectasis. My personal philosophy is that MAC is everywhere, all the time. I make sensible adjustments (keep my equipment clean, no hot tubs, no indoor pools, dig in the dirt only in a mask...) So far I have managed safely for over 4 years.
Other opinions may differ.
Sue