I have read that Mycobacterium has an affinity for charcoal which is in Britta filters. We use one in our house but change the filter monthly instead of 2 months that is recommended on the box. I would not get the "extended" filter that is available.

@pamelasc1 Hi Pam - I was able to find one study that directly addressed charcoal water filters. Here is a link: https://www.atsjournals.org/doi/full/10.1513/AnnalsATS.201301-013FR.
Also, keep in mind the mycobacteria infects by aerosolized droplets being inhaled, not from being ingested, so you need to decide if using a Britta or similar device for drinking water is a risk you are able to tolerate. In my case, we use drinking water taps which we filter, and I force my husband to change them every month. I figure since MAC/NTM have been found in bottled water as well as tap/municipal water, the risk of having a filter is one I accept in order to have palatable water. I do, however, limit my exposure to water vapors - no hot steamy showers, run the fan, get out of the bathroom and dress in the bedroom while the vapor dissipates... And, sadly, stay out of and away from hot tubs (a social gathering place in our community.) And I use boiled water for cleaning our nebulizers and breathing devices.
By the way, do you have a well, or municipal water?
Sue