I made these Knikon:

http://www.mensswimsuitboard.com/for...read.php?t=716

pool attire
 

We know what is required in France by the simple signs displayed at their pools but it seems that in DC the DPR gives out far more detail on the regulations:
http://www.popville.com/2013/07/dpr-...-for-dc-pools/

Your basketball shorts must be left at home but you can bring your long* swim briefs and your short swim briefs.

*what this contradiction in terms means is beyond my comprehension but the illustration of long appears to show jammers.

What they have listed as a swim thong actually looks like a G string.

the rules
 

LOL - looks ok also to wear your underpants as long as they are not white
(it would seem the DPR needs a competent person in the R section who knows something about swimmers and swimming to do a redraft!)