Singapore, often described as one of the cleanest in the world, has just emerged more than scathed from the Year of Public Hygiene in 2024. This was the result of Waterloo run by SMU Principal Lecturer of Statistics Rosie Ching and her 222 SMU undergraduates. Together in just five weeks, they performed comprehensive and detailed on-site surveys of more than 2,600 public toilets across 1,428 coffeeshops, hawker centres, train stations and shopping malls, whilst interviewing a total of 4,905 people, comprising 510 employees and 4,395 customers, on the state of public toilets. A staggering 98 percent national coverage was an unprecedented level, smashing records across the eight years of this national survey of public toilets in coffeeshops and hawker centres.
Hundreds more toilets in shopping centres and train stations were visited and given the same survey treatment as those in coffeeshops and hawker centres. In 2024, shopping centre toilets ranked far and away significantly superior to those in coffeeshops and hawker centres where 90 percent of toilet attributes were rated dirtier than reasonable in the latter, with wet floors, absent, dirty or overflowing rubbish bins, unclean toilet bowls and seats, choked urinals, filthy squat pans, inadequate or absent toilet paper, stained mirrors and doors, absent to insufficient ventilation, with more than 8 in 10 cleaning schedules either absent or not updated, some dating back to 2020. The only attributes rated reasonable were taps and soap. The smell of coffeeshop toilets presented a significantly worse assault on the olfactory glands compared to that in hawker centres, both lying in the “breathe lightly” category.
The closer cooking facilities were to the toilets in coffeeshops and hawker centres, the significantly dirtier the toilets. This was also observed in 2016, 2020 and 2023, with the correlation extremely strong in 2024, a significant cause of concern in public health because of all the citizens interviewed, 94 percent of food-handling workers identified themselves as using the toilets at their working premises. Voluminous photographic and video evidence also paid abundant testimony to the filth in these toilets and presence of raw food placed or handled near these toilets.
With more than 100 variables of cleanliness of toilet bowls, taps, mirrors, floors, ventilation, toilet dispensers, paper and more, Waterloo found coffeeshop toilets dirtier than in 2023 on the Toilet Cleanliness Index (TCI). The sole silver lining were hawker centre toilets on the uptick in cleanliness in 2024. Unisex toilets remained statistically the filthiest, hardly moving in the Year of Public Hygiene and woefully stuck at the lowest levels in 2024, with the large majority located in coffeeshops.
The overarching public perception of these coffeeshop and hawker centre toilets was that of “Dirty”. Four years ago, 30.22 percent thought these toilets were at least “Clean”, but this took a jaw-dropping beating to 8.5% in 2024. Over the four years since human interviews in Waterloo began, 8,367 have said such toilets are “Very dirty” to “Dirty”, making up almost 6 in every 10 citizens interviewed. As of late 2024, the modal response remained “Just as dirty” by more than 50 percent of the 14,316 citizens interviewed since.
A staggering 92 percent believed efforts to clean up toilets were “completely not” or “only somewhat” effective. Of these, 60 percent explicitly rated these efforts as “mostly ineffective” or worse. With a measly 8 percent optimistic about Singapore’s Keep Toilets Clean campaigns, the voice of the masses has rung clearly that much more needs to be done to improve the sorry state of public toilets that serve as daily essentials for so many citizens in these popular food centres.
In excess of nine in ten of customers declared public toilets in need of major overhauling, rating them as “dirty”. Although 81 percent now use these toilets for a small call of nature, almost 70 percent would shun them for a big call of nature, the highest avoidance rate in nine years of study. The majority also thought current enforcement of cleanliness standards in public toilets at coffeeshops and hawker centres is too lax and recommended heavier fines and more monitoring, with 78.2 percent saying coffeeshop operators do not clean their toilets according to advisories by the Minister for Sustainability and Environment in Singapore.
Ms. Ching’s work has elevated public awareness of sanitation and enforced accountability. Waterloo’s findings have been shared widely through media coverage reaching every corner of Singapore, on primetime TV, radio, and the leading newspapers across all national languages. The force of Waterloo has inspired government initiatives like the Toilet Improvement Program, fines for non-compliance, with future plans focused on tracking and ensuring exemplary cleanliness standards, showing firm and uncompromising societal impact, historically unparalleled for any undergraduate teaching project.
Behind all these movements, Waterloo is an educational juggernaut to be reckoned with, where Ms. Ching’s students wield their statistical training and drill through volumes of data, unwrapping messages behind the numbers to paint the landscape with never-before-had statistics, to drive societal change in Singapore. They experience how such a national-scale project drives action and accountability. They witness the Waterloo’s influence on the country and experience education that transcends the four walls of the classroom. Student feedback consistently and overwhelmingly testify to the transformative nature of this experience when Ms. Ching adroitly connects their learning to society’s problems.
Waterloo has engaged Members of Parliament, mayors, policymakers, leaders, and industry leaders, driving momentum for change on a national level. Ms. Ching’s teaching and long-term vision have smashed through traditional barriers by combining rigorous data science with effective dissemination, advocacy, and partnerships, relentlessly demonstrating education as a formidable force for social change, policy impact and sustained community engagement.
The ten-year-long and ongoing Waterloo owes its monumental success to Ms. Ching and her students as comrades-in-arms, who have nurtured it into an unstoppable force as a precedent for impactful and sustainable educational initiatives worldwide.
Ms. Rosie Ching (centre in red), a.k.a. the Chief Sitting Plumber leading her Waterloo students, with Aditya Rahman (with microphone) in a rallying cry.
Said Waterloo student Aditya Rahman, “Mathematics and me have always had a rocky relationship. I dreaded and feared it, praying I did not have to study it again. But when I enrolled in university, lo and behold, statistics was a must. I shoved it to Year 2 but eventually had to face my fears and take the leap into the unknown. Which is when I entered Ms. Ching’s classes and Waterloo! My entire Waterloo journey of surveying toilets in hawker centres, coffeeshops and human stakeholders has been one indescribably unique experience, a far cry from everything I have studied to date. If I had told my younger self that surveying toilets would form one of my most memorable moments in SMU, I am confident that he would have laughed in my face. However, I now understand the application of statistics in the real world and why it matters. Waterloo has genuinely given me a deep perspective on the impact statistics has on the world. Ms. Ching has inspired me significantly to be a better man in all things. I am thankful for this and am truly grateful to have spent the last 3 months in the presence of Ms. Ching.”
Says Ms. Ching, “To my incredible comrades in this mission, my students, I pay especial tribute. I struck uncountable matches many times before Waterloo caught fire, nurtured those sparks and flames into a healthy bonfire, one that now roars with voices, numbers, and an unwavering resolve to change the world. This isn’t just research collecting dust on some shelf; it’s a movement, powered by thousands of voices that matter, our people, our families, our elderly, our young, our cleaners, our workers. This is for Singapore.”
For her trailblazing teaching and impactful work, Ms. Ching was Highly Commended in the Financial Times’ Responsible Business Education Awards 2025 for Waterloo, the only honoree for South-East Asia amongst global entries. She was also inducted into the inaugural SMU Teaching Excellence Hall of Fame Award in 2024, was the QS Reimagine Education Gold Winner for Blended and Presence Learning in 2023, and was bestowed the World Toilet Organization Hall of Fame Award that same year. For two years running, both Ms. Ching and her students also received Singapore’s national LOO (Let’s Observe Ourselves) Award for public sanitation in the Individual and Community categories respectively, for nine years of pro-bono and outstanding contributions to public sanitation.
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