Sanitation and Drinking Water Issue Category consists of two indicators:

1) Unsafe sanitation, measured as the proportion of a country's population exposed to health risks from their access to sanitation, defined by the primary toilet type used by households. It is log-transformed and given 40% weight in the aggregation.

2) Unsafe drinking water, measured as the proportion of a country's population exposed to health risks from their access to drinking water, defined by the primary water source used by households and the household water treatment, or the treatment that happens at the point of water collection. It is log-transformed and given 60% weight in the aggregation.

Both indicators are measured using the number of age-standardized disability-adjusted life-years (DALYs) lost per 100,000 persons. The issue category varies from 0 to 100.