When I needed pool therapy, I began by contacting local PT practices to see who had an ongoing relationship with a location that had a therapeutic pool. Then I chose the most convenient one. They supervised my initial in-pool sessions, then I was able to purchase a pass to use the therapeutic pool on my own (within their schedule) as long as I had at least one session per month with my therapist in the pool. I learned this process when my Mom was similarly treated post-stroke by pool therapy.
These were both done in heated, accessible pools - not a whirlpool. Because it was a therapy pool, and I was an "established" client, I was able to use the various tools they had there.
Sue