I agree with your concern @christielynn and also have been searching for scientific conclusions about risk in geographic locations in order to make a decision about spending time in SC where we have a condo ( I live in PA) . I have been anxious about being in the SC coastal area. We found a small research study about NTM infection rate in CF patients in FL that showed a 9x increase in rate of NTM infection for those who lived within 500m of water. I have posted that link below. We have decided to sell our place in SC as it is surrounded by water in the low country. It is a very personal and difficult decision without a lot of guidance. I hope you can find peace in the process of deciding where to settle as NTM is present to some degree everywhere. You can’t mitigate the outside environment that surrounds you so I think location is an important decision.
Best wishes.
https://www.researchgate.net/profile/Raid-Amin/publication/311885929_Household_proximity_to_water_and_nontuberculous_mycobacteria_in_children_with_cystic_fibrosis/links/5a60e59c45851517c7af0120/Household-proximity-to-water-and-nontuberculous-mycobacteria-in-children-with-cystic-fibrosis.pdf

That is an interesting question, but because NTM is rare, most studies are relatively small case studies, not necessarily research studies. And in those I have reviewed, there was little or no consideration of other factors like higher risk occupations, or common age (e.g. agriculture or poultry plant workers, or in the case of Florida, large population of older women (higher risk group) who may have relocated from colder climates because they already had lung problems.
Also, other assets may outweigh a slightly higher risk - such as ready access to high quality medical care or proximity to family and friends for getting help.
So, the bottom line is that some areas may have a higher risk of infection, most likely to people who have no idea of the risk or their susceptibility, and therefore taking no precautions. Now that you are diagnosed, and know the steps to take to protect yourself, does it really matter where you live?

I continue to live in the 2 homes I occupied when I became infected. My water is tested, but I'm sure it came from gardening, whether the soil itself, the mulch or plants. So I take many precautions there - having someone else do any and all dusty work while I stay safely in my filtered home. And wearing sleeves, gloves and mask when interacting with plants and soil, wetting things down and showering and laundering clothes when done. My garden shoes don't even enter the house. On windy/dusty days I wear a mask outdoors. 3 years and counting off meds and no reinfection.

This is how I live with Bronchiectasis, asthma and the risk of MAC or Pseudomonas reinfection.