We all weigh the risks vs. the potential harm. No doctor can tell you for sure where pseudemonas is living. There are some studies done, many from other countries. But none of them are conclusive - they can't rule out seemingly harmless sources, such as your own kitchen sink or tub as the source from which you have contracted pseudemonas. Having said that, the conventional wisdom that many CFers live by say this - lakes and rivers are the most risky. Community pools are risky too depending upon their adherence to the schedule for cleaning and chlorine in particular. Chlorine will likely kill bacteria in the water before it gets to you. It will not kill it in your body, but in the water. You can also get it in private pools, but they tend to be kept cleaner - following the maintenance and chlorine schedule if you know it. Our local YMCA keeps such a high level of chlorine that it hurts my eyes to walk into the pool room. So I feel comfortable there. If your relative has a pool they don't bother regularly maintaining, then it's not likely to be better than the river. Oceans on the other hand are not only safe, but therapeutic. (Hence the australian experience). The high salt content in the water is an incredible cleanser. Even in your body. The Australian surfers breathe in water on a regular basis - great for the lungs. Great for sinuses too. But don't be fooled. Salt water pools that some people install are NOT therapeutic. They clean the water with a very low level of salt rather than chlorine. It is not sufficient to kill bacteria and in fact allows a breeding ground to exist. They are worse than most pools. In addition standing water is a risky source. Your sink, puddles in the sandbox, the puddle of water left inside the plastic bowl that comes out of the dishwasher etc. are risky. Keep everything your CFer uses dry. I've seen posts where people use the hairdryer on their toothbrush after use, though I think that may be overkill.Pseudemonas is indeed everywhere. In the dirt, in your cats ear infection, in puddles. It's very difficult to avoid. I hope I've helped.