What recommendations do you offer for patients who have a peritoneal dialysis catheter and who wish to swim?  

Exercise is an important part of health maintenance for all individuals, including those with ESKD requiring peritoneal dialysis (PD). Swimming is an excellent form of exercise for PD patients because it is not associated with increased intra-abdominal pressure, and is a low-impact aerobic activity ...

Agree, avoid fresh water, hot tubs, etc. Pools (chlorinated) and seawater are considered "fine". I personally think a colostomy bag is a deal-breaker.