The COVID-19 pandemic reshaped expectations for public restroom hygiene, design, maintenance, and building-water management. While many early concerns required further study, the pandemic made it clear that a restroom should be managed as a complete indoor environmental system—not merely as a collection of fixtures.
Researchers, facility professionals, architects, and public-health officials took a closer look at the factors that influence restroom conditions: flushing aerosols, ventilation, handwashing, touchpoints, cleaning procedures, traffic flow, drains, and water stagnation.
For facility managers, schools, hospitals, airports, stadiums, office buildings, and other high-occupancy properties, the lasting lesson is simple: effective public restroom design must support hygiene, accessibility, occupant flow, water efficiency, and maintainability at the same time.
Flushing Aerosols and Urinal Plume
One topic that received widespread attention during the pandemic was the possibility of aerosol generation during toilet and urinal flushing.
A urinal plume refers to the small droplets and airborne particles that may be released when a urinal is flushed. In 2020, researchers at Yangzhou University in China used computer simulations to examine how particles might move after a urinal flush. Their modeling suggested that some particles could travel upward quickly, potentially reaching the lower body area of the person standing in front of the fixture.
The research generated substantial media interest because it raised questions about aerosol exposure in busy public restrooms during COVID-19. However, the study modeled particle movement; it did not prove that flushing urinals transmitted COVID-19.
Its broader significance was that it reinforced a well-established concern in restroom hygiene: flushing can create aerosols, and some aerosols may contain microorganisms. A 2023 systematic review similarly found that toilet flushing can generate bioaerosols, although the real-world risk of airborne or surface transmission from those aerosols remains difficult to measure precisely.
For facility managers, this supports practical steps such as maintaining flush fixtures properly, improving ventilation where feasible, keeping fixtures clean, and avoiding restroom layouts that place users too closely together.
Toilet Plume and Restroom Hygiene
Toilet plume is closely related to urinal plume but has been studied more extensively because toilets handle human waste, which can contain many types of microorganisms.
Research has shown that flushing can release small droplets and particles into the surrounding air. Some studies have also suggested that aerosolization may continue through additional flush cycles, particularly if the toilet bowl or nearby surfaces remain contaminated.
That does not mean toilet plume is a proven major route of infection in everyday restroom use. The contribution of flushing aerosols to actual disease transmission remains uncertain and continues to be studied. Still, the subject highlights why restroom operations should account for ventilation, cleaning, lid use where applicable, fixture maintenance, and proper hand hygiene rather than treating flushing as an isolated issue.
The pandemic did not establish that public restrooms are inherently dangerous. Instead, it encouraged a more complete understanding of how restroom fixtures, airflow, surfaces, and user behavior interact.
Hand Dryers, Touchpoints, and Occupant Flow
COVID-19 renewed attention to the full handwashing process, including soap delivery, drying methods, surfaces, and congestion around sinks.
Studies have explored whether electric hand dryers can disperse microorganisms from hands into the air or onto nearby surfaces. Some research has found that microbes can become airborne or settle around drying stations. That evidence does not mean every electric hand dryer creates a meaningful health risk, but it does support a layered approach to restroom hygiene: effective handwashing, practical drying options, sufficient cleaning, and adequate ventilation.
A touchless restroom can reduce the number of surfaces occupants need to touch. Common touchless restroom technologies include:
Sensor-operated faucets
Automatic soap dispensers
Touch-free flush valves
Sensor-based paper towel dispensers
Automatic or low-contact doors
Hands-free waste receptacles
Touchless equipment should not be treated as a complete solution. Even in a modern touchless restroom, visitors may still contact partition latches, grab bars, countertops, door handles, baby-changing stations, railings, and ledges.
The goal is to reduce unnecessary touchpoints while making the remaining surfaces easy to access, clean, inspect, and maintain.
Common Restroom Touchpoints
Stall doors, locks, and handles
Entrance and exit door hardware
Faucets and sink controls
Soap dispensers
Paper towel dispensers
Flush handles or manual override buttons
Grab bars
Countertops and ledges
Baby-changing tables
Waste receptacle lids and openings
Designing for Traffic Flow
Before the pandemic, many public restroom projects emphasized fixture counts, aesthetics, durability, water conservation, and available floor area. Those priorities remain important, but COVID-19 added a stronger focus on crowding and occupant movement.
Congestion can occur at several predictable points:
Entry and exit doors
Sink banks
Soap and towel dispensers
Hand-drying stations
Narrow aisles between fixtures
Accessible stalls and turning areas
Cleaning closets or supply-storage locations
A high-performing public restroom should be planned around more than maximum fixture density. Designers and facility managers should consider whether people can enter, use fixtures, wash their hands, dry their hands, and leave without creating unnecessary bottlenecks.
Key public restroom design considerations include:
Adequate circulation and queuing space
Accessibility and clearances
Appropriate ventilation
Sufficient handwashing capacity
Well-placed drying options
Easy access for custodial staff
Durable, cleanable finishes
Reduced high-touch surfaces
Clear occupant flow from entry to exit
The most efficient restroom is not necessarily the smallest restroom. It is the one that supports safe use, effective cleaning, accessibility, durable performance, and efficient maintenance.
Refillable Soap Dispensers and Handwashing Communication
Handwashing remains one of the most important ways to reduce the spread of many respiratory and gastrointestinal illnesses. But the way soap is stored, dispensed, refilled, and maintained also matters.
Older refillable bulk soap dispensers may pose hygiene challenges when they are repeatedly “topped off” without being fully emptied, cleaned, dried, and maintained. Contamination can occur if staff add fresh soap to a dispenser that contains older product or if the dispenser reservoir is not cleaned according to the manufacturer’s instructions.
For many facilities, sealed soap-cartridge systems can simplify maintenance and reduce concerns associated with poorly maintained bulk reservoirs. The best choice depends on the facility’s budget, product availability, maintenance practices, dispenser compatibility, and cleaning program.
Clear handwashing signage also remains valuable. Well-placed reminders near sinks and exits can encourage proper handwashing without requiring major capital improvements.
Effective restroom handwashing messages are:
Easy to read at a glance
Located near sinks or mirrors
Written in plain language
Appropriate for the building’s users
Supported by stocked soap, water, and drying supplies
Reinforced by reliable cleaning and maintenance
Cleaning and Disinfection After COVID-19
The pandemic changed how many organizations think about restroom cleaning. Cleaning is not only about appearance. It removes dirt, organic matter, and microorganisms from surfaces. When needed, properly applied disinfectants can reduce pathogens on surfaces after cleaning.
An effective restroom cleaning program requires more than purchasing disinfectant. It depends on consistent procedures, staff training, quality control, and the correct use of products.
Custodial teams should be trained in:
Selecting appropriate cleaning and disinfecting products
Following label instructions and dilution requirements
Allowing proper disinfectant contact time
Preventing cross-contamination between restroom areas
Managing cloths, wipes, mop heads, and cleaning tools
Prioritizing high-touch surfaces
Using personal protective equipment when needed
Handling and storing chemicals safely
Cleaning equipment itself can spread contamination if it is used incorrectly. Reusing contaminated cloths, mop water, or poorly maintained tools can move soil and microorganisms from one surface to another rather than removing them.
A modern restroom-cleaning program should include documented procedures, employee education, supply management, inspection routines, and regular performance reviews.
Floor Drains, Trap Seals, and Sewer Odors
Floor drains and plumbing traps are often overlooked until odors develop. Yet they are an essential part of a healthy, well-maintained restroom.
A plumbing trap holds water beneath a sink, floor drain, toilet, or other fixture. This water seal helps prevent sewer gases and odors from entering occupied spaces. If a restroom is vacant or a drain is not used for an extended period, the water in the trap can evaporate.
When a trap dries out, unpleasant odors and sewer gases can enter the restroom. During the 2003 SARS outbreak, investigators examined defective plumbing and drainage conditions as potential contributors to disease spread in some building environments. That history does not mean every floor drain is an infectious-disease hazard. It does demonstrate why trap maintenance, drainage design, and plumbing inspections matter.
Facility teams should include seldom-used floor drains, sinks, showers, and other water fixtures in their routine inspection schedule. Maintaining trap seals can prevent odor complaints and help preserve better indoor conditions.
Stagnant Water and Building Water Management
One of the most important facility-management lessons from the pandemic involved water systems in buildings that were vacant, partially occupied, or operating with reduced demand.
When water sits in plumbing for long periods or moves very slowly, several water-quality and maintenance problems may develop:
Reduced disinfectant residuals
Conditions that may support Legionella growth
Corrosion and possible release of metals such as lead or copper
Dry plumbing traps and sewer-gas odors
Deteriorated water quality when a building reopens
Problems in low-use fixtures, dead legs, and rarely occupied building zones
The U.S. Centers for Disease Control and Prevention advises building owners and operators to assess water-system risks before reopening buildings after extended closures or major reductions in occupancy.
Legionella is not related to COVID-19 and does not cause COVID-19. It is a group of bacteria that can cause Legionnaires’ disease, a serious type of pneumonia. Under favorable conditions, including stagnant water and certain temperature ranges, Legionella can grow in building water systems.
Before reopening or returning a low-occupancy building to full operation, facility managers should use a building-specific water-management plan. Depending on the property and its risks, this may involve flushing hot- and cold-water systems, checking temperatures, restoring water to dry drains, reviewing disinfectant residuals, inspecting seldom-used fixtures, and consulting qualified water-management professionals.
What Facility Managers Should Take Forward
COVID-19 did not turn every public restroom into a high-risk environment, and not every pandemic-era concern has been proven to be a major disease-transmission pathway. That distinction is important.
However, the pandemic did accelerate a more comprehensive approach to restroom management. Today’s public restroom strategy should consider the combined effect of fixture design, water efficiency, ventilation, occupant behavior, cleaning methods, touchpoints, plumbing maintenance, and building-water quality.
The most important lasting priorities are:
Maintain reliable handwashing access with soap, water, and drying options
Use touchless restroom technology where it adds practical value
Improve ventilation and airflow where feasible
Design layouts that reduce unnecessary crowding
Keep high-touch surfaces easy to clean and inspect
Train cleaning teams on products, procedures, and cross-contamination prevention
Maintain drains, trap seals, and plumbing fixtures
Manage stagnant water during low occupancy or building shutdowns
Incorporate water efficiency without compromising hygiene or maintainability
Public restrooms will continue to evolve as building owners balance hygiene, user expectations, accessibility, sustainability, and operating costs. The pandemic’s central lesson is that resilient restroom design depends on systems thinking: the fixtures, users, plumbing, airflow, cleaning program, and water management plan all need to work together.
Klaus Reichardt is the CEO and founder of Waterless Co., Inc., in Vista, Calif., a pioneer in water-efficiency solutions. He founded the company in 1991 to create a new market segment in plumbing fixtures focused on water conservation. A frequent writer and presenter on water conservation, Reichardt can be reached at klaus@waterless.com.
To contact Klaus, click here.
Sidebar: Stagnant Water Risks in Public Buildings
Water stagnation occurs when water remains unused or moves slowly through a building’s plumbing for an extended period. Schools during summer break, offices with hybrid schedules, hotels with low occupancy, and temporarily closed public facilities can all experience stagnation-related water issues.
Dry Drain Traps
Plumbing traps beneath sinks, floor drains, and other fixtures normally hold water. This water barrier helps block sewer gases and odors from moving into the occupied space.
During periods of nonuse, water can evaporate from the trap. Once dry, the drain can allow unpleasant odors and sewer gases into the restroom.
Facility managers should inspect rarely used drains and fixtures as part of preventive maintenance and reopening procedures. Refilling dry traps with water is often the first step. In suitable applications, approved trap-seal products may provide additional protection when used according to manufacturer directions and applicable code requirements.
Legionella and Water Quality
Stagnant water can contribute to conditions that support Legionella growth and other water-quality problems. Extended shutdowns can also increase concerns about disinfectant loss, corrosion, and possible lead or copper release from plumbing materials.
A building-specific water-management plan may include:
Flushing hot and cold water throughout the plumbing system
Checking water temperature and disinfectant levels where appropriate
Inspecting low-use fixtures and areas of slow water movement
Refilling dry drain traps
Reviewing drinking-water quality when warranted
Following applicable CDC, EPA, state, provincial, and local requirements
Working with qualified building-water professionals for complex systems or elevated risks
The Bottom Line
Stagnant water is more than an inconvenience or odor issue. In low-occupancy or temporarily closed buildings, water-system management should be part of the overall facility-maintenance and reopening plan.
A proactive approach can help maintain water quality, reduce odor complaints, protect occupants, support regulatory compliance, and identify plumbing problems before normal building operations resume.
Key Words: public restroom hygiene, commercial restroom design, restroom health and safety, toilet plume, urinal plume, restroom ventilation, touchless restroom fixtures, stagnant water, Legionella, water management, restroom sanitation
