Basic water quantity

Q: I need information on the international quantity standards of basic water supply. I have read 20 litres is a minimum, but does that include hygiene for example?
(Researcher, South Africa)

Answer: 20 liters includes personal hygiene, according to the WHO Technical note for emergencies : minimum quantity needed for domestic use in emergencies:

"Medium term allocation: 15-20 Lpcd (sustainable for a few months)
• Drinking: 3-4 Lpcd
• Food preparation, cleanup: 2-3 Lpcd
• Personal hygiene: 6-7 Lpcd
• Laundry: 4-6 Lpcd"

See Reed (2005) below for more tables and figures on water quantity and its use:

Also, the WHO states on their web site:

Based on estimates of requirements of lactating women who engage in moderate physical activity in above-average temperatures, a minimum of 7.5 litres per capita per day will meet the requirements of most people under most conditions. This water needs to be of a quality that represents a tolerable level of risk. However, in an emergency situation, a minimum of 15 litres is required. A higher quantity of about 20 litres per capita per day should be assured to take care of basic hygiene needs and basic food hygiene. Laundry/bathing might require higher amounts unless carried out at source.

Source: http://www.who.int/water_sanitation_health/emergencies/qa/emergencies_qa5/en/index.html

And, Les Roberts argues in his article "Diminishing standards: How much water do people need?":

"UNHCR's [1] guideline regarding water quantity in the 1960s was adopted from that of the WHO [2], 30 litres per person per day (l/p/d). This standard was not adapted from empirical data contrasting healthy populations with unhealthy populations, but was established by "experts" estimating the amounts of water needed for cooking, washing, drinking, etc., and then adding up the total daily requirements.

In the 1970s the WHO standard was reduced to 20 l/p/d and the UNHCR target followed suit.

In 1982 UNHCR declared the desirable goal to be 15 to 20 litres [3] and by 1992 it was calling for a minimum allocation of 15 l/p/d. But "when hydrogeological or logistic constraints are difficult to address, a per capita allocation of 7 litres per person per day should be regarded as the minimum 'survival' allocation. This quantity will be raised to 15 litres per day as soon as possible" [4].

Again, the new target was based on what was actually occurring given the relief communities' funding and workload, and was in no way based on human health data. At the time, the average water provision to an African refugee was perhaps only 12 l/p/d, in spite of the UNHCR standard [5].

While the new target is a "survival" ration, millions of refugees throughout the world currently receive between 7 and 15 l/p/d. The new "survival" target enables project managers to say that, while we are not providing an ideal quantity of water, provisions are well above the survival level. Thus, the diminishing quantity standard is fundamentally to provide political protection rather than public health protection.

[…]Thus, from a public health perspective, our guidelines should say "15 to 20 l/p/d are required during the acute phase of a crisis, but less may be sufficient in the later phases", rather than vice versa."

More data and guidelines on (minimum) water quantity requirements are available in:

Nozaic, D. (2002). Water quality and quantity
In: Wijk-Sijbesma, C.A. van (ed.) and Smet, J.E.M. (ed.) (2002). Small community water supplies : technology, people and partnership. (Technical paper series / IRC; no. 40). Delft, The Netherlands, IRC International Water and Sanitation Centre.
Download the PDF file (109KB) or go to the IRC web site to download it

Minimum standards in water supply, sanitation and hygiene promotion
In: Sphere Project (2004). The Sphere project : humanitarian charter and minimum standards in disaster response. Rev. ed. Geneva, Switzerland, Sphere Project.

Howard, G. and Bartram, J. (2003). Domestic water quantity, service level and health. Geneva, Switzerland, World Health Organization (WHO).

Reed, B. (2005). Minimum water quantity needed for domestic use. (WHO technical note for emergencies ; no. 9).
Dowload the PDF file (517 KB)

Roberts, L. (1998). Diminishing standards: How much water do people need?
Extract from FORUM: Water and war.