Sustainable Development Goals - 17 Goals to Transform our World

Ensure availability and sustainable management of water and sanitation for all

Indicator 6.3.2: Proportion of bodies of water with good ambient water quality

Proportion of bodies of water with good ambient water quality

This table provides metadata for the actual indicator available from US statistics closest to the corresponding global SDG indicator. Please note that even when the global SDG indicator is fully available from US statistics, this table should be consulted for information on national methodology and other US-specific metadata information.

Actual indicator available
Actual indicator available - description
Date of national source publication
Method of computation The GEMS/Water1 water quality index approach is used as a general model to calculate the index, in which measured determinand values are compared to guideline values (proximity to target approach): 1. Proximity-to-target (PTT) scores for each determinand at single monitoring sites are calculated as the difference between the temporal average (for the accounting period) of the determinand concentration and the target divided by the range between the (winsorized) minimum or maximum of the measured determinand concentration (for exceedance and non-exceedance targets, respectively) and the target. The PTT scores are scaled to the range between 0 and 100, where 100 indicates that the target is met and decreasing scores indicate an increasing distance from the target. 2. The water quality index (WQI) at site level is computed as the arithmetic mean of the site-level PTT scores for the selected determinands. The WQI scale can be divided into different water quality categories, ranging from very bad to excellent. The thresholds for these categories are country specific and should be reported in the monitoring system by the individual countries 3. For the spatial aggregation at the basin level and country level, the water bodies are divided into stretches of homogenous quality (between consecutive monitoring stations). 4. The final indicator is calculated from the proportion of the stretches with good quality compared to all water bodies assessed.
Scheduled update by national source
U.S. method of computation
Comments and limitations
Date metadata updated
Disaggregation geography
Unit of measurement
Disaggregation categories
International and national references
Time period
Scheduled update by SDG team

This table provides information on metadata for SDG indicators as defined by the UN Statistical Commission. Complete global metadata is provided by the UN Statistics Division.

Indicator name Proportion of bodies of water with good ambient water quality
Target name By 2030, improve water quality by reducing pollution, eliminating dumping and minimizing release of hazardous chemicals and materials, halving the proportion of untreated wastewater and substantially increasing recycling and safe reuse globally.
Global indicator description Proportion of water bodies (area) in a country with good ambient water quality compared to all water bodies in the country. 'Good' indicates an ambient water quality that does not damage ecosystem function and human health according to core ambient water quality indicators. Concept: Water quality is estimated based on a core set of five determinands that inform on major water quality impairments present in many parts of the world: total dissolved solids (TDS); percentage dissolved oxygen (% DO); dissolved inorganic nitrogen (DIN); dissolved inorganic phosphorus (DIP); and Escherichia coli (E. coli). As monitoring capacities and coverage vary between countries, a monitoring ladder is proposed. On the first rung, the number of determinands not meeting national water quality guidelines based on the existing monitoring sites are used to estimate the water quality. On the second rung, a water quality index is used to combine the determinand values in a statistically more robust manner, and the monitoring coverage increased. On consecutive rungs, the monitoring coverage can be step-wise increased and complementary determinands covering additional aspects of ambient water quality can be included depending on the national capacities and requirements enabling the indicator to inform on the status of ambient water quality in a more comprehensive way.
UN designated tier 2
UN custodial agency UNEP (Partnering Agencies: UN Water)
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Agency Staff Name
Agency Survey Dataset
Link to data source