No offense, but what happens if a person with a contagious disease coughs or spits into holy water?
They contaminate it. What did you think would happen?
It would have to be dumped into the sacristy sink or dirt and be replaced. :shrug:
There are certain protocols for disposing of things which are blessed. Usually being poured out into dirt, being burned, or being buried. Never being thrown in the trash. Depends on the item. The holy water would, of course, be disposed of in this proper way, so long as it was reported to a proper authority.
I hve never seen anyone spit into holy water; and I have never met anyone who did.
As to someone sneezing or coughing near holy water - nothing is going to happen,as no one is going to pay any attention to it.