Personally if I knew there were 3 babies living in a house where drugs were being sold, I would report that to social services, but I'm in the UK and I don't know how cps work.
To me a child in a home drugs are being sold from is at risk. Drugs being left around, shady people coming to the house, robberies etc, what if someone gets a grudge or the couple don't manage to pay THEIR dealer?
However, if they're not dealing from the house and you don't have any reason to believe the kids are being neglected, then no, there is nothing to report.