A Shit Flow Diagram (SFD) is an easy-to-understand advocacy and decision-support tool comprising a report (SFD Report) which contains a graphic (SFD Graphic). An SFD summarises service outcomes in terms of the flow and fate of excreta in urban areas. It includes a qualitative assessment of the context in which service delivery takes place and a complete record of data sources.  The process of developing the report is as important as the report itself; use of the SFD method enables a standardised assessment of excreta flows in urban areas. Due to the sensitivity around the term “shit” the following terms are often used interchangeably: Excreta Flow Diagram or Faecal Waste Flow Diagram.

The SFD Graphic indicates where the problems lie in an urban area, but without understanding the local context you cannot understand why these situations occur.  The SFD Report will help to answer questions such as “Why is only half of the excreta produced onsite collected?” or “why is only half of the wastewater that reaches the treatment facilities treated?” The SFD Report provides information on the institutional frameworks, roles and responsibilities, regulatory aspects, and other issues that directly or indirectly impact the provision of sustainable sanitation services. It also includes the assumptions used to prepare the SFD Graphic.

A good way to start the SFD process is by reading the SFD Manual (Version 2.0, July 2017).

This tells you what data you need to collect and how to collect it:  Volume 1 of the Manual is useful to guide you through the data collection process whilst Volume 2 will help you to familiarize yourself with the terminology used by the SFD PI such that a common understanding of terms and consistent language is used. We also recommend that you read through previous SFD Reports, especially if one has been produced for a city or town in your country, as this will highlight data sources which you can use and will give an idea of the layout and content of the report. All SFD reports are available via https://SFD.susana.org/SFD-worldwide. If you require help remember that you can always contact us via the help desk http://SFD.susana.org/toolbox/SFD-helpdesk or by email This email address is being protected from spambots. You need JavaScript enabled to view it.. A pool of experts, all of whom have developed  SFD  Reports using this process, are happy to answer any questions and guide you through the process.

The SFDs Worldwide tab on the web portal includes a large number of completed SFD Reports. These clearly set out the assumptions used and the basis of the data and estimates used to prepare the SFD Graphics in each case.

This process originated from the work of Andy Peal, Barbara Evans, and the World Bank on faecal sludge management which is documented in the following papers:

• Fecal sludge management (FSM): analytical tools for assessing FSM in cities. By Andy Peal, Barbara Evans, Isabel Blackett, Peter Hawkins and Chris Heymans. Published September 2014, 4 (3) 371-383; DOI: 10.2166/washdev.2014.139. http://washdev.iwaponline.com/content/4/3/371
• Fecal sludge management: a comparative analysis of 12 cities. By Andy Peal, Barbara Evans, Isabel Blackett, Peter Hawkins and Chris Heymans. Published December 2014, 4  (4)  563-575;  DOI: 10.2166/washdev.2014.026. https://SFD.susana.org/resources/recommended-readings?details=2212

The SFD Portal now offers a new feature that enables users to translate the graphic generator and the resulting SFD graphic into multiple languages, which is a significant advancement towards improving the overall dissemination, sustainability, and relevance of the tool. Additionally, the portal provides manuals and templates that are readily available in multiple languages to offer further assistance. While the SFD portal supports translations using the Google Translation function, we need to obtain your consent before using external services. You can modify your settings at any time via the menu item in the footer menu. For more information, please refer to our Data Policy.

The SFD Process methodology includes the most widely accepted sanitation-related technical terms and their definitions according to several high quality resources and papers. All the technical terms used in the SFD Process are explained in the SFD Glossary which also includes some of the commonly used local variants. However, it is recognised that there are regional variations in both technical term usage and their definitions. To keep the SFD Graphic clear and uncluttered, very few technical terms are displayed on the Graphic; instead generic terms are used to describe both the sanitation chain and service outcomes in terms of the flow and fate of excreta.

Where changes to these and other terms help local understanding, users are encouraged to highlight these changes and all other assumptions in the SFD Report.

Other tools have been developed that also explore the flows of faecal waste through the sanitation service chain. These include:

• The Faecal Waste Flow Calculator, developed by the IRC (www.ircwash.org/tools/faecal-waste-flow-calculator), approximates shit flow volumes along the sanitation service chain. As mentioned in FAQ 5, numerous assumptions are required when converting the percentage of the population’s excreta to volumes and we recommend caution.
• The Performance Assessment System (PAS) for urban water supply and sanitation developed by CEPT University (www.pas.org.in). This tool is based on a questionnaire which is filled in for a city or town to assess performance indicators on water, sanitation, and solid waste management. It then identifies key strengths and areas for improvement.

The SFD Graphic is a visual representation that enables stakeholders to identify service outcomes in terms of the flow and fate of excreta produced by the population. Excreta which is safely managed and move along the sanitation service chain are represented by green arrows moving from left to right in the graphic, while excreta which are unsafely managed are represented by red arrows. Unsafely managed flows discharging to the environment are represented by red arrows turning towards the bottom of the graphic. The width of each arrow is proportional to the percentage of the population whose excreta contribute to that flow. 

The point at which the arrows drop down to the bottom of the graphic, gives a general indication of how far the excreta has travelled from the initial population centre. For example open defecation normally occurs in the ‘local area’ close to where people live, whereas untreated wastewater in open drains or sewers may flow out of the ‘local area’ through the ‘neighbourhood’ to the edge of a ‘city’.  The endpoint of the different arrows provides an indication of the likely location and scale of discharge of unsafely managed excreta to the environment.

The SFD Graphic represents the excreta produced by the total population of an urban area from the point where it originates. It therefore includes excreta from households, schools, institutional toilets, hospitals, workplaces etc. The places where excreta originate are known as categories of origin in the SFD Manual (see Volume 1, section 5.2.1, Version 2.0). Excreta flows may need to be split between different categories (for example home and school) and these must be clearly stated in the report.

The SFD Graphic shows the percentage of the population whose excreta are considered to be either safely managed or unsafely managed. Safely managed and unsafely managed in this context indicates the likelihood of a population being exposed to a hazard as a result of the flow of excreta through the sanitation service chain, rather than absolute risk. Estimating the absolute risk would require accurate information on the level of hazard (concentrations and volumes of known pathogens at any point in the service chain), etiology and dose-response curves for those known pathogens, and information on the timing, duration and age profile of population exposed to the hazard; assessing these would require significant additional data collection and analysis.

The width of each arrow on the SFD Graphic is proportional to the percentage of the population whose excreta contribute to that flow, not volumes of excreta or waste. This is because data on the types of sanitation systems used are normally available via national census data or health surveys, and are based on the number of people. To convert this data to volumes would require a large number of assumptions to be made such as:

• the amount of waste each person produces per day
• the amount of water used to flush the waste in water-based systems
• the amount of leakage in sewers etc.

Typically very little data are available to enable accurate or credible estimates to be made on the basis of volumes. Population percentages are also relatively easy to comprehend for non-technical stakeholders.

The SFD Graphic and process is related to the sanitation service chain; the service chain for solid waste would be different.  The SFD Graphic Generator cannot be used directly to model solid waste flows across a city or town, but the existing SFD Manual (Version 2.0, July 2017 and process could be adapted to develop solid waste flow diagram tools.