The modern toilet is an unobtrusive piece of technology that has a major impact on health and quality of life. At first glance, it may seem that “a toilet is a toilet,” but the reality is far more diverse: from flush bowls with a trap, to squat toilets, to vacuum systems on airplanes, and waterless composting solutions. At the same time, access to safely managed sanitation is not evenly distributed—according to the latest WHO/UNICEF (JMP) overview, global coverage of safely managed sanitation reached roughly 58% in 2024, while hundreds of millions of people still lack a decent toilet and hygiene facilities at home. This trend, along with the Sustainable Development Goals (SDG 6), is regularly highlighted by the UN’s World Toilet Day campaign. More in the sources cited directly in the text: UNICEF/WHO JMP 2025 update and UN-Water World Toilet Day.
The basic principle: a toilet as a barrier between people and waste
The essence of every toilet is simple: to separate people from fecal waste as reliably as possible, and then to remove or process it safely. The classic “Western” flush system uses a water seal (trap) that prevents sewer gases from entering the room; when you flush, gravity pushes the contents through the bend and into the drain. An alternative is the squat toilet, preferred in many countries for easier cleaning and a posture that many consider more hygienic. Increasingly common are technologies that minimize water use—or avoid it entirely—such as dry and composting systems.
Flushing, the trap, and sewers: why it works the way it does
In standard toilets, water serves both as the transport medium and as an odor seal. The trap (water seal) forms a barrier that sewer gases can’t pass through; during flushing, the shape of the ceramic bowl creates brief suction (negative pressure). In cities, the toilet connects to the sewer network and the waste travels to wastewater treatment plants, where it undergoes mechanical, biological, and often tertiary treatment. In remote areas, this function is replaced by a cesspit or septic tank, which holds sewage locally and requires regular pumping and safe disposal.
Squat vs. “sitting”: cultural differences and practical reasons
Squat toilets are common in parts of Asia, Africa, and Southern Europe, and many people consider them more hygienic because you don’t touch anything. Seated toilets are the standard in Europe and North America, where they are often paired with a separate bidet or integrated bidet seats. The differences aren’t only cultural—they also depend on water availability, space, habits, and maintenance demands.
Japanese “smart” toilets and bidets: when the WC does more than just flush
Japan is synonymous with high-tech toilets featuring heated seats, integrated bidets, air drying, and automatic nozzle cleaning. These functions are designed to improve hygiene, reduce toilet paper use, and increase comfort—while the core principle remains the same: water creates a barrier and carries waste into the sewer. A long-running overview of why toilets are linked to health and comfort is also provided by global campaigns such as UN-Water’s World Toilet Day.
Vacuum toilets on planes and trains: flushing without liters of water
Vacuum systems use negative pressure and smooth pipes to quickly “suck” waste into sealed tanks. The advantages are significantly lower water consumption, a lower risk of leaks, and operation in vehicles where gravity or ample clean water can’t be taken for granted. It’s an engineering solution tailored to extreme conditions—see more in the video below.
Waterless and composting solutions: when there’s no water, biology steps in
Dry toilets without flushing use urine separation and the separation of solid waste, followed by controlled composting. The right carbon-to-nitrogen ratio, oxygen access, and moisture control ensure decomposition and sanitization. These systems are promising where water is expensive, sewers don’t exist, and a circular economy approach makes sense. The ISO 30500 standard for non-sewered sanitation systems also targets these “off-grid” technologies, setting safety and performance requirements for prefabricated units with integrated waste treatment (ISO 30500).
“Not for everyone”: global access and health
Despite technological progress, safely managed sanitation remains unevenly available. UNICEF/WHO JMP reports that coverage of “safely managed sanitation” rose to roughly 58% over 2015–2024, yet a substantial share of humanity still lacks a home toilet that safely separates waste from contact with people and the environment (UNICEF/WHO JMP 2025 update). The consequences are significant: the spread of intestinal infections, contamination of water sources, and long-term impacts on education and the economy. That’s why the UN commemorates World Toilet Day every year on November 19, calling on governments and cities to invest in sustainable sanitation for all (UN-Water World Toilet Day).
The future of toilets: standards, innovation, and rethinking the WC from the ground up
Alongside traditional sewer networks and treatment plants, a parallel path is emerging: non-sewered systems that neutralize or process waste on site into a safe form. The international ISO 30500 standard describes requirements for such integrated devices—from collection to local treatment of outputs so they are safe for people and the environment (ISO 30500). A major wave of innovation was also sparked by the Reinvent the Toilet Challenge, launched by the Gates Foundation to develop toilets that work without network connections, with minimal water and energy use and low operating costs—while reliably destroying pathogens (Gates Foundation – Reinvent the Toilet).
Accessibility and inclusion: toilets for children, seniors, and people with disabilities
Well-designed toilets must work for everyone: step-free doors and stalls, grab bars by the bowl, enough space to maneuver a wheelchair, changing tables for children, as well as menstrual hygiene needs and safe storage areas. In public restrooms, lighting, ventilation, and a sense of safety also matter. These standards aren’t only about comfort—they reduce barriers to education and work for millions of people.
What to watch for when traveling: practical tips
When traveling, expect toilets to look different from what you’re used to at home. In some countries, a bin for used paper is common; elsewhere, you’ll find a hand-held bidet sprayer and less reliance on paper. In some places, public toilets are paid; elsewhere, they’re only available to customers. It helps to carry a small bar of soap or hand sanitizer and to respect local practices—from how flushing works to where used paper should go.
Videos: short explanations of toilet types
How airplane toilets work (Purdue University)
A short expert explanation of vacuum systems and why airplanes don’t need liters of water per flush.
How to use Japanese toilets (washlet)
A practical guide and demonstration of the most common electronic bidet functions.
Composting toilets: principle and practice
A basic overview of separation, ventilation, and why waterless systems make sense off the sewer grid.
Conclusion: toilets as an infrastructure priority
Toilets are more than comfort—they’re small devices with an outsized impact on health, education, and the economy. From a ceramic bowl to smart, waterless units, all solutions ultimately aim for the same goal: to process waste safely and protect both people and the environment. Progress is real, but the road to universal access is still long—and it’s worth speeding up through investment in proven and emerging technologies.
Sources
- UNICEF/WHO JMP (2025): “Progress on household drinking water, sanitation and hygiene 2000–2024 (JMP 2025 update)” – https://data.unicef.org/resources/jmp-report-2025/
- UN-Water: “World Toilet Day” – https://www.unwater.org/our-work/world-toilet-day
- ISO: “Non-sewered sanitation systems — Prefabricated integrated treatment units — General safety and performance requirements (ISO 30500:2018)” – https://www.iso.org/standard/72523.html
- Bill & Melinda Gates Foundation: “Reinvent the Toilet Challenge and Expo” – https://www.gatesfoundation.org/our-work/programs/global-growth-and-opportunity/water-sanitation-and-hygiene/reinvent-the-toilet-challenge-and-expo
Jana
I like turning curiosity into words, and writing articles is my way of capturing ideas before they slip away — and sharing them with anyone who feels like reading.
