New Scientific Study Shows Toilet-Related Coronavirus Transmission Risk

You’re keeping six feet between yourself and others in public and avoiding crowded public spaces, especially indoors. You’re wearing a mask outside of the house. You’re keeping your home’s surfaces as germ-free as possible to avoid even the lower risk of surface contact infection. You thought you were doing everything necessary to keep yourself and your family safe from the novel coronavirus causing the COVID-19 pandemic. But you didn’t count on toilet flushing being a potential risk. Now it is showing up on the list of infection hazards.

A study just released from the Physics of Fluids journal by the publishing arm of the American Institute of Physics (AIP Publishing), indicates that flushing toilets after defecation by infected individuals creates plumes of virus-laden droplets. Here’s how that works, according to the report: “As water pours into the toilet bowl from one side, it strikes the opposite side, creating vortices. These vortices continue upward into the air above the bowl, carrying droplets to a height of nearly three feet, where they might be inhaled or settle onto surfaces. These droplets are so small they float in the air for over a minute.”

The computer simulation used for the study showed that these aerosolized droplets last long enough to be breathed in by the next user in a busy setting. “One can foresee that the velocity will be even higher when a toilet is used frequently, such as in the case of a family toilet during a busy time or a public toilet serving a densely populated area,” said co-author Ji-Xiang Wang, of Yangzhou University.

Manufacturers Respond

Global fixture manufacturers are aware of this study and looking at ways to address it. “Our team is working to improve the reliability with proximity and automatic technology, targeting our auto open/close toilet seats, auto flush technology for toilets and urinals and even auto handwashing faucets,” comments James Walsh, a vice president with Lixil Group, corporate parent of American Standard and DXV.

Flushing your toilet from a smartphone app and motion-controlled seats and lids might have seemed frivolous before, but both can now be helpful in avoiding plume spread. Duravit features both in its 2019 product line.

Kohler and Toto also have smartphone apps available; select models offer automated flushing and lid/seat operation.

Residential Toilet Solutions

There’s little you can do about public toilets, other than bringing wipes for the seat, wearing a mask to reduce the potential of breathing in infected air, and staying home as much as possible, but you do have options to reduce your risk at home.

Not using your home’s bathrooms is clearly not a solution, and nature dictates when that happens, but there are a few things you can do to reduce flushing risks for you and your family:

• Have each person close the toilet lid before flushing to keep droplets from rising out of the toilet. This can be done by tenants, homeowners and guests alike — no renovations needed.
• Have each user clean the toilet seat before using it, the study authors suggest, since floating virus particles could have settled on its surface, and wash hands carefully after flushing to reduce spread from a flush button or bathroom door handle.
• If anyone in your household is known to be infected, give that individual his or her own bathroom to use, if possible, at least temporarily during the infection period.
• Invest in a toilet or toilet seat that automatically lowers the lid. Flush afterward.
• If you’re planning to remodel your master suite or create a master bath addition to your home, consider separate water closets for each user if you share it.
• If you’re purchasing a new home for you and your family, consider a Jack and Jill configuration for your children’s bathrooms, so that each child has a separate toilet.

Long-term Residential Changes

It’s likely that COVID-19, and the awareness that this probably won’t be the last infectious disease to reach our shores, will change how our homes are designed and constructed. Potential changes were shared by eight thought leaders in this space in March.

Veronika Miller-Eagleson, founder and CEO of Modenus Media, a comprehensive online resource for the design industry, predicted that “smart toilets will be the biggest Christmas gift for 2020 and beyond! Home builders must plan for these now with electrical pre-wiring near the toilet.”

Peter Chapman, senior book editor with niche home design and lifestyle publisher The Taunton Press suggested that “all those ‘bonus’ spaces developed in the heyday of big building might better be considered as isolation rooms now. Even with couples living alone, there may be a need for separate facilities for each in case one or the other is exposed.” This new study points out that those facilities should probably include their own toilets.