One black lady once answered this. I will quote her here.

"It's a matter of interest. I don't know if you know many black people, but if you did you would probaly find that many black woment spend a lot of time making sure their hair looks nice which can cost up into the hundreds. Swimming is for the most part a social activity at first. Meaning people don't usually swim alone especially when learnining. So, if the black women aren't in the water, you probaly won't see a whole lot black men in the water. This is not by any means the only reason... only one of the reasons you don't see black people in the water and the one I'm most familiar with.

It's a matter of health and beauty. Generally speaking too much water especially clorinated is not good for black hair. It tends to dry it out and cause breakage. It also tends to dry out the skin which means we have lotion up more.

There are tons of other reasons too. It's a matter of time and money.There a black single mothers who have to work who don't have the time or the money teach or pay for the swim lessons. Children can't go near water by themselves especially if they can't swim so....

It's a matter of cultural and exposure. Many blacks who are willing to take extra care of hair and skin, who have the money and time, generally aren't exposed to how much fun swimming is until later in life because of the above reasons.

Finally, many black children grow up with more singing, dancing, football, cheerleading, church groups and other activities that aren't so good i.e. drugs etc instead of being exposed to tennis, swimming, golf (until recently), and other expensive lessons.

It has little or nothing to do with genetics.

I hope this helps."

As you can see it is mostly societal influences with very little if any medical influences. Vast majority of people who own pools are Caucasian. This doesn't mean that Blacks are oppressed from owning pools but it is greatly a societal influence.

It is no secrete the the clicks in society plays a major upbringing. Most blacks are neighbors with Blacks, most Hispanics are neighbors with Hispanics, most Asians are neighbors with Asians and most Caucasians are neighbors with Caucasians. We each have unique cultures and lives that influence us. We are different and I am thankful for that. If everyone was the same life would be dull beyond imagination.

As for medical I can see skin and hair color being an issue. People with darker complexions tend to suffer drier skin in many situations. Sunlight, heat and most forms of radiation can burst, burn or dry out cellular structures faster on those with a dark complexion. Testing with nuclear radiation has revealed that skin samples of darker complexion tends to burn at significantly lower doses than that of lighter skin.