There is a good movie about rats on TV called Rats. I think the best part has already come and gone though. A lot of kids are in a swimming pool when suddenly the rats start streaming in from all sides. Everyone starts screaming as if this is a big problem, forgetting for a moment that the chlorine in the water would make them relatively clean. You'd have nothng to worry about.

Some people worry unnecessarily about urination in public swimming pools, but the chlorine takes care of it, pretty much. In fact, when you pour urine into a swimming pool, the chlorine causes it to change its chemical makeup, so it's no longer really "urine" at all.

How much urine would be acceptable, before a "saturation point" were reached? Realistically, almost any conceivable amount. I guess it would depend on your "comfort level" whether you wanted to go on slobbering about in there doing laps or lengths or whatever.