The human right to water and sanitation (HRWS) is a principle stating that clean drinking water and sanitation are a universal human right because of their high importance in sustaining every person's life. It was recognized as a human right by the United Nations General Assembly on 28 July 2010. The HRWS has been recognized in international law through human rights treaties, declarations and other standards. Some commentators have based an argument for the existence of a universal human right to water on grounds independent of the 2010 General Assembly resolution, such as Article 11.1 of the International Covenant on Economic, Social and Cultural Rights (ICESCR); among those commentators, those who accept the existence of international ius cogens and consider it to include the Covenant's provisions hold that such a right is a universally binding principle of international law. Other treaties that explicitly recognize the HRWS include the 1979 Convention on the Elimination of All Forms of Discrimination Against Women (CEDAW) and the 1989 Convention on the Rights of the Child (CRC).

Drinking water or potable water is water that is safe for ingestion, either when drunk directly in liquid form or consumed indirectly through food preparation. It is often supplied through taps, in that case, it is also called tap water. Typically in developed countries, tap water meets drinking water quality standards, even though only a small proportion is actually consumed or used in food preparation. Other typical uses for tap water include washing, toilets, and irrigation. Greywater may also be used for toilets or irrigation. Its use for irrigation however may be associated with risks.