Should you flush with the lid open or closed? Experts have a new theory

The invisible spray is never OK.

Flushing the toilet with the lid down does not stop the spread of small germs, a study published Thursday in the American Journal of Infection Control found.

Researchers discovered microscopic viral particles all over the restroom when a person flushes the toilet — whether the lid is up or down. 

“A lot of people said all you have to do is close the lid and the problem is solved,” lead researcher and microbiologist Charles Gerba told USA Today.

“All that air when you flush goes somewhere, and it carries the viruses that are in the toilet bowl out of it.”

Previous research has shown that shutting the lid reduced the spread of germs, but Gerba noted that these studies focused on larger viral particles.

While the study found that closing the lid did not reduce the overall contamination of the bathrooms, it did conclude that having the lid down did change the trajectory of the germs.

When the toilet was closed, there was slightly higher contamination to the left and in front of the toilet but slightly lower contamination to the right of the toilet.

Instead of worrying about keeping the toilet closed, the study found that disinfecting the toilet, toilet water and nearby surfaces is the best way to reduce the spread of germs.

The experts found that the bathroom was cleaner when the toilet bowl was scrubbed with a brush and a hydrochloric acid disinfectant.

“You really have to make sure you always clean the toilet seat and other areas in the restroom,” Gerba insisted.

And, of course, don’t forget to wash your hands with soap and water.

Experts advise washing your hands for 20 seconds, but the germs in the bathroom can linger much longer after flushing the toilet.

Germs can survive on bathroom surfaces for about 30 minutes after a flush, according to a study published in Antimicrob Resist Infect Control.

To keep your stuff and yourself clean, the experts advise against keeping products such as your toothbrush and cosmetics out in the open and using your phone in the bathroom.

This reminder is especially important as health experts continue to warn of the tripledemic — the surge of RSV, flu and COVID-19 cases.