Can maggots swim in water

Yes. To test this, put a small piece of leftover meat in a plastic cup and leave it out for flies. They will lay their eggs in it. After a few days, cover the meat with water. After a total of eight days, maggots will crawl out of the meat and escape as flies into the air. If you don't want flies, put the cup into a plastic grocery bag, tie the "handles" of the bag and dispose of it after seven days total. Good luck in ridding us of flies. BTW, each fly lays about 150 eggs at a time. Doing the above, early in the season, prevents perhaps a hundred thousand flies by September. Their life cycle is pretty short from being laid as an egg to laying 150 eggs at a time.