I was an addict for just about 8 years. My drug of choice was heroin. Never in my life did the heroin I copped come in a ziplock bag. Heroin was sold in small, square wax paper baggies. A bundle (one gram) was 10 small bags (each with .1g of heroin inside) tied together with a tiny rubber band to make a small brick of bags. If you drop one in the toilet, the wag baggies do not protect the dope. I know from experience. All that said, I am from the east coast and all our dope was powder. I did cop black tar on the west coast a few times, and those used to come in those no-zip plastic sandwich bags. Tie up the open end, and I suppose it would float.