Q: How long can waterborne parasites survive on the outside of a Lexan bottle?
L.B., Minneapolis, MN
A: Put away the hazmat suit; most bugs die shortly after the droplets dry. The exception is giardia, whose tough outer shell (called a cyst) allows it to survive after water evaporates. The best defense against all potential bugs is to wipe down the bottle and let it dry in the sun for an hour. To prevent pathogens from hiding out in the cap threads, loosen the top and allow treated or filtered water to splash into the threads before tightening it again.