It is illegal to blow your nose in public.

The Law Explained

During the rampant spread of tuberculosis and the 1918 influenza pandemic, cities took extreme, desperate measures to maintain public hygiene. Waterville supposedly passed this ordinance to stop people from dispersing germs into the open air by blowing their noses aggressively on the street. While nobody is going to arrest you for using a Kleenex today, it remains on the books as an artifact of historic health panics.