The aim of the study was to describe and map the availability (number, density, and distribution) of public toilets in major international cities in different countries by city population and area.

The study had an observational/descriptive design. Twelve cities in 9 counties that had available data were selected: Minneapolis-St. Paul (MSP), New York City (NYC), and Philadelphia in the United States [US], Greater London including city of London in the United Kingdom [UK], Greater Sydney including city of Sydney [Australia], Paris [France], Berlin [Germany], Brussels, [Belgium], Toronto, [Canada], Osaka, [Japan], and Seoul, [South Korea]. Data of the location and number of public toilets were acquired from Parks and Recreational Departments in the US. Data in other countries were acquired from online open data archives created and managed by national or local governments. Data of a city’s area, boundaries, and population were from a national Census survey and/or statistics database.  
Public toilets were defined as publicly owned and managed facilities in parklands (i.e., park/recreation areas in US cities and Osaka) or in open spaces (i.e., park/recreation areas + transportation stations, or on street in other cities). As analysis units, “administrative” areas were used for Berlin [the areas were Bezirke/borough or district], Brussels [commune/ municipality], London [borough], NYC [borough], Osaka [Ku/ward], Paris [Arrondissements/district], Seoul [Gu/ward], and Toronto [ward]. “Statistical” areas were used for MSP and Philadelphia [Census Tract] and Sydney [Statistical areas–Level 4]. Administrative areas were local entities directly controlled by the municipal government, e.g., city council. Statistical areas were designated by government agencies for statistical/demographic purposes, e.g., Census. Geocoded locations of public toilets in cities were mapped and counted along with the administrative or statistical areas using ESRI’s ArcGIS version 10.5.1. Total population and total areas (km2) of cities were calculated by summing the population and area (km2) in individual area units. The mean area was calculated by total area/individual area units. The density of public toilets was calculated by population (number of toilets/100,000 residents) and by total area (km2) of cities. Visual presentation using maps was used to illustrate the distribution of public toilets in each city.

The characteristics of the population, area, and public toilets are presented in Table 1 for cities with public toilets in parklands and in Table 2 for cities with public toilets in open spaces. The population of the cities ranged from medium (<1 million) in MSP to very large (>10 million) in Seoul. The most densely populated city was Paris (21,394 residents per km) followed by Seoul, Osaka, and NYC. Sydney had the lowest population density (407 residents per km2). 
The density of public toilets per area (km2) of parklands was highest in Osaka (1.44) followed by NYC (0.79 toilets) (Table 1). MSP had the most toilets in parklands per 100,000 residents (24.10). The density of public toilets per area of open spaces (km2) was highest in Paris (3.47) and Seoul (2.11) and lowest in Berlin, Sydney, and Brussels (Table 2). Sydney had the most toilets in open spaces per 100,000 residents (54.77 toilets) while Brussels and Berlin had the fewest, with <5 toilets per 100,000 residents.  
Regarding distribution of toilets, visual examinations using maps showed that public toilets in MSP and Toronto were fairly evenly distributed across parkland areas. Conversely, the distribution of public toilets in open spaces in Brussels was highly concentrated in one area, the region of Brussel [Dutch]/Brexelles [French]. A couple of boroughs in London had no public toilets reported by the local government.

The availability of public toilets varies among international cities. Considering city population and area, availability is high in Paris, Seoul, MSP, Philadelphia, and Sydney and low in Berlin and Brussels. The density of public toilets in open space areas per km2 seems to be directly related to population density in Paris and Seoul but the opposite is seen in Sydney. Sydney has the lowest population density but the highest toilet density in open spaces per km2. The lower density of public toilets in parklands areas per km2 in MSP and Toronto seems to be associated to the even distribution of toilets across areas. However, MSP has the highest number of parklands toilets per population density while Toronto has the lowest number. Brussels has the fewest toilets per population and their toilets are the least distributed.  
Limitations: The data of all public toilets (i.e., those provided/managed by private companies or temporary ones) in cities were not available to collect. No standardized international criteria exist for determining the boundaries or unit areas of a city. The exact location (e.g., street address) of a public toilet vs. its general area was sometimes not provided in the software.

Adequate public toilets in park and recreational sties or on routes to destinations may be beneficial to persons with incontinence to achieve being continent while in public. Toilet availability may also assist these persons to be active and engage in physical or social activities [1] in their neighborhoods.  A shift towards a community-based healthcare model seems to be effective for community-living people with chronic incontinence [2]. Improvements in the availability of public toilets may mediate the negative feelings such as depression or social isolation often experienced by people with incontinence. Finally, urban planning should introduce health aspects of toilet availability into the designs of cities as part of the responsibilities of cities to improve health and quality of life in their residents.

Greed C. Inclusive urban design: Public Toilets. Oxford, UK: Architectural Press; 2003.
Wagg AS, Newman DK, Leichsenring K, van Houten P. Developing an internationally-applicable service specification for continence care: systematic review, evidence synthesis and expert consensus. PloS one. 2014; 9(8):e104129. doi: 10.1371/journal.pone.0104129