The Global Centre for Risk and Innovation (GCRI)
Safe drinking water and sanitation are counted in whether a household’s water is available when needed, free from contamination and on the premises, and whether excreta are safely contained, treated and disposed. The counting is global, the delivery is local, and the gaps open fastest in crises. This page sets out how access and safety are measured and what the evidence serves.
Water NexusWireframe of the working environment, not a live screen. Names and values are placeholders.
Treatment, safety, infrastructure and equity. The dossier below sets out how the risk develops, what is measured, where the data come from, how it is modelled and who decides.
Access is classed from surface water to safely managed service. Moving up the ladder needs infrastructure, management and affordability together; any one missing drops the rung.
Faecal contamination enters through broken pipes, intermittent supply, unsafe storage and poor sanitation nearby. Microbial risk rises sharply during floods and outages.
Arsenic, fluoride, nitrate and lead are geogenic or infrastructural, chronic rather than acute, and invisible without sampling.
Disasters and displacement multiply the population per source and collapse sanitation first. Outbreaks follow within weeks unless provision is planned.
Where this page’s subject sits in the world: boundaries and context now, the field layers when the interactive map loads.
MapWorld map in the Equal Earth projection, land and boundaries from Natural Earth (public domain). The interactive map loads through the Nexus Foundry plugin (globe or flat view).
The systems this subject touches, the method at its core and the decisions it informs.
Each indicator carries its unit, its cadence, the kind of source behind it and the evidence label a value would carry. No values are shown: a programme supplies them under its own authority.
| Indicator | Unit | Cadence | Source type | Label |
|---|---|---|---|---|
| Population with safely managed drinking water | percent | annual | Household surveys, administrative data | OFFICIAL |
| Population with safely managed sanitation | percent | annual | Household surveys, administrative data | OFFICIAL |
| E. coli detection in supply samples | percent of samples positive | monthly | Laboratory sampling | OBSERVED |
| Arsenic and fluoride exceedance | percent of sources above guideline | survey | Source testing | OBSERVED |
| Intermittency | hours of supply per day | daily | Utility records, sensors | OBSERVED |
| Persons per functioning water point | persons | per site | Site assessments | ESTIMATED |
The topic as a computational graph: named sources feed the methods, an evidence review gates the outputs, and the decisions stay with the authorities that hold them.
Fig. 02Nodes carry their type, two metric rows and a state; connectors show what feeds what; dashed frames name the owners; the timeline is the cadence. Design of the pipeline, not a record of a run.
Named public datasets and institutional records, each with its licence class. Sources by agreement are used only under their terms and never republished.
| Source | What it gives | Licence class |
|---|---|---|
| WHO and UNICEF Joint Monitoring Programme | National and subnational access estimates and the service ladders | Free and open, attribution |
| Demographic and Health Surveys and MICS | Household-level water and sanitation data | Terms per survey programme |
| National water quality surveillance | Sampling results by supply and source | By agreement with each agency |
| Water Point Data Exchange | Rural water point functionality records | Open, attribution |
| Humanitarian cluster assessments | Crisis-period provision and gaps | Terms per cluster |
Water Nexus prepares evidence. The decisions below are taken by the authorities named, under their own rules, and never by the platform.
| Who decides | The question | Evidence this page serves |
|---|---|---|
| Health and water ministries | Where safely managed service is furthest from target and what closes the gap | Access maps with uncertainty; contamination risk by supply type |
| Utilities and local authorities | Which supplies need continuous chlorination, pipe renewal or storage advice | Sampling results against intermittency and outage records |
| Humanitarian coordinators | Where provision is below standards and outbreak risk is rising | Persons per water point, sanitation coverage, surveillance signals |
Safety rests on multiple barriers: protecting the source, treating water by coagulation, filtration and disinfection, maintaining pressure and residual disinfectant in the network, and safe storage in homes. A failure at any barrier, such as low pressure that lets contaminated groundwater enter pipes, can undo the others.
Sanitation separates people from excreta. Where it fails, pathogens reach water sources and spread diarrhoeal and other diseases, with the heaviest burden on young children. Floods, power cuts and drought can disable treatment and sewerage at the moment communities need them most. Emerging contaminants and antimicrobial resistance add new questions.
Water safety planning identifies hazards and control measures from catchment to consumer. Its value depends on regular verification and honest records.
Laboratory and field testing, increasingly supported by online sensors and observation networks. Sampling captures moments, not continuous conditions.
Household surveys and utility records describe access, reliability and affordability. Informal settlements and intermittent supplies are often under-recorded.
| Method | Applied here | Canonical page |
|---|---|---|
| Water and environmental engineering | Water and environmental engineering in this field | STEM Commons |
| Spatial statistics and geostatistics | Spatial statistics and geostatistics in this field | STEM Commons |
| Sensors, IoT and observation networks | Sensors, IoT and observation networks in this field | STEM Commons |
| Geospatial information systems | Geospatial information systems in this field | STEM Commons |
| Uncertainty quantification and model validation | Uncertainty quantification and model validation in this field | STEM Commons |
Survey-based access estimates carry sampling error and lag by years. Water quality is sampled, not continuous, so contamination between samples is unobserved. Geogenic hazards need source-level testing that many areas lack. Water Nexus does not deliver services; it prepares evidence for those who do.
The current service level is R0: information and enquiries. An enquiry receives a reference and names the next step; applications, payments, compute allocations and registrations open only when their team, terms and review capacity exist.