The information below is taken from a paper, Reducing Environmental Exposure to NTM, by Joseph Falkinham, PhD, May 3rd, 2021

Flush and Run Water in Unused Lines to Reduce Water Age. Water age refers to the time water stays in pipes in houses. The average water age in household plumbing is 1-3 days. Residence of water for over 3 days leads to a loss of disinfectant and the resulting growth of NTM and other waterborne pathogens. Increased water age can occur in plumbing in areas of a house that are unused; for example, in an unused bathroom or unoccupied wing of a house. The solution is simple, have someone not at risk for NTM disease to flush commodes and run water (5 min) in taps in unused bathrooms and in seldom used laundry tubs, half baths, and outside faucets.

Having another family member or friend flush the system will reduce your exposure to NTM. Enjoy your getaway.