The International Drinking Water Supply and Sanitation Decade (IDWSSD) was observed between:

The International Drinking Water Supply and Sanitation Decade was observed over 1981 to 1990 to widen access to safe water and sanitation.

The span 1991 to 2000 came after the decade and was not the observed period.

The years 1971 to 1980 fall before the decade began.

The range 1965 to 1975 predates the initiative entirely.

The decade aimed to bring clean drinking water and basic sanitation to all by its close.

It laid groundwork later carried forward into the water and sanitation development goals.