Not sure what exact law is, but there is new compliance about pool/spa drains for short term rentals, commercial property, and it was for new places and existing pools came in to comply at a later date. There had to be two drains instead of one and had to pull water in from sides of drain rather than top of drain. That is what we were told from a registered pool person. Not sure if existing private pools had to comply. This is the state of Florida, not sure of other states. Definitely a concern, though, and scary. Often times when we are in hotels we see little ones swimming, diving, and doing about anything in the spas with parents not supervising and staff not saying anything.
Sandy