Apparently, the dirtiest public toilets at hawker centres and coffee shops are in neighbourhoods like Boon Lay, Bukit Panjang and along the Singapore River. On the flip side, very clean ones can be found in Marina South, Outram, Yishun and the Western Water Catchment. All that is according to a survey done by 178 Singapore Management University (SMU) students in August as part of an introductory statistics course.
The data collected was turned into a 'Toilet Cleanliness Index', which you can view by region to see which areas have public toilets in hawker centres and coffee shops that range from 'very dirty' to 'average' to 'very clean'. Factors taken into account include the distance between the toilets and the cooking stations, the cleanliness of the toilets inside and outside the cubicles, and the toilet designs.