How much water is needed in emergencies

TECHNICAL NOTES ON DRINKING-WATER, SANITATION AND HYGIENE IN EMERGENCIES Updated: July 2013

9.1

TECHNICAL NOTES ON DRINKING-WATER, SANITATION AND HYGIENE IN EMERGENCIES

How much water is needed

in emergencies

Water is essential for life, health and human dignity. In extreme

emergency situations, there may not be sufficient water

available to meet basic needs and in these cases, supplying

a minimum level of safe drinking-water for survival is of

critical importance. Insufficient water and the consumption

of contaminated water are usually the first and main causes

of ill health to affect displaced populations during and after a

disaster. This technical note considers the minimum quantities

of water that are required for survival in emergencies.

Factors affecting water

requirements

The amount of water required

to support life and health in an

emergency varies with climate, the

general state of health of the people

affected and their level of physical

fitness. Of equal importance in

deciding how much water is needed

are the expectations people have.

A poor rural community may have

far lower expectations concerning

the quantity of water that is essential

for life than people used to living in

a wealthy urban environment. As

a result, the poorer community is

likely to consume less.

The Sphere Standards

Attempts have been made in the

past to define minimum water

quantities required in emergencies.

In 2004, a cluster of relief agencies

developed the document entitled

Sphere Humanitarian Charter and

Minimum Standards in Disaster

Response which set standards

for the minimum level of services

people affected by an emergency

should receive. For water supply,

it states that all people should

“have safe and equitable access

to sufficient quantity of water for

drinking, cooking and personal and

domestic hygiene” and that public

water points should be “sufficiently

close to households to enable use

of the minimum water requirement”.

Most major relief agencies and

their donors have accepted the

Sphere Standards as the foundation

for acceptable relief services.

Sphere also describes indicators

which relate to the delivery of the

standards, including water quantity

standards. Indicators are not

binding like the standards; rather,

they are suggestions of what might

be a reasonable interpretation of the

standards.

This technical note uses the Sphere

indicators for guidance.

Carefully consider your local situation

to be sure that they are appropriate for

the conditions you are dealing with.

How much water does an

individual use?

People use water for a wide variety

of activities. Some of these are more

important than others. Having a few

litres of water to drink each day, for

example, is more important than

having water for personal hygiene

or laundry, but people will still want

and need to wash for the prevention

of skin diseases and meeting other

physiological needs. Other uses of

water have health and other benefits

but decrease in urgency as Figure 9.1

demonstrates.

Figure 9.1. Hierarchy of water requirements (after Maslow’s hierarchy of needs)

Drinking10L

20L

30L

40L

50L

60L

70L

Cooking

Personal washing

Washing clothes

Cleaning home

Growing food

Sanitation and waste disposal

Business (crops, livestock)

Gardens, recreation

Short-term

survival

Medium-term

(maintaining)

Long-term

(lasting solution)

Generally

increasing

quantity

Decreasing

quality

9.2

TECHNICAL NOTES ON DRINKING-WATER, SANITATION AND HYGIENE IN EMERGENCIES

How much water is needed in emergencies

Figure 9.2. Water does not have to be of the same quality for all uses

Priorities for water

People do not always have

predictable needs. In some cultures,

the need to wash sanitary towels

or to wash hands and feet before

prayer may be perceived to be more

important than other water uses.

Talk to people to understand their

priorities. People may also have

quite specific needs concerning the

use of water for anal cleansing.

Women and men may have

different priorities. Women may be

concerned about basic household

water requirements and water to

wash during menstruation, whilst

men may have concerns about

livestock. In the assessment, waste

spillage and leaks also need to be

taken into consideration.

The Sphere Standards suggest

a basic survival-level water

requirement to use as a starting

point for calculating demand

(see Table 9.1). However, research

indicates that 20 liters per capita per

day is the minimum quantity of safe

water required to realise minimum

essential levels for health and

hygiene. Therefore, efforts should

be made to incrementally secure

this amount for each individual.

Water sources and quality

People do not have to get all their

water from a single source. They

may be provided with bottled

drinking-water, but use water from a

stream to wash their clothes.

As demand for water increases,

generally the quality required for

each use can be reduced. Water for

cleaning a floor does not have to be

of the same quality as drinking-water

and water for growing subsistence

crops can be of a lower quality still.

Sanitation and water

requirement

The type of sanitation provided has

a big impact on water requirement.

Water-borne types of sanitation,

such as flush toilets, require a

large volume of water (up to 7L per

person per use).

Pit latrines, or simple pour-flush

toilets (Figure 9.3) have a much

lower water requirement.

Accessibility

Even if plenty of water is provided,

there may be other limits to its use,

such as the time taken for people

to travel and queue to collect it. If

it takes more than 30 minutes to

collect water, the amount they will

collect will reduce (see Figure 9.4).

Providing washing and laundry

facilities near the water points

reduces the need to transport water.

Box 9.1. Minimum provision

of domestic water containers

Two vessels 10-20L for

collecting water plus one 20L

vessel for water storage, (narrow

necks and covers) per 5 person

household.

Type of need Quantity Comments

Survival (drinking and food)

Basic hygiene practices

Basic cooking needs

2.5 to 3 lpd

2 to 6 lpd

3 to 6 lpd

Depends on climate and individual physiology

Depends on social and cultural norms

Depends on food type, social and cultural norms

Total 7.5 to 15 lpd lpd: Litres per day

Table 9.1. Simplified table of water requirements for survival (per person)

Source: Adapted from Sphere. Also see WHO, 2011. Guidelines for drinking-water quality,

4th edition. World Health Organization, Geneva. http://www.who.int/water_sanitation_health/

publications/2011/dwq_chapters/en/index.html

Figure 9.3. Pour-flush pit latrines

9.3

TECHNICAL NOTES ON DRINKING-WATER, SANITATION AND HYGIENE IN EMERGENCIES

How much water is needed in emergencies

Sphere (2004) suggests that

in emergencies the maximum

distance from any household

to a water point be 500 metres

and the maximum waiting time

to collect water be 15 minutes.

Water for

non-domestic use

Water is essential for many other

services provided in emergencies,

especially health care. Affected

communities may also want to use

water for religious activities and

agriculture. Users, not providers,

decide how they will use a scarce

supply of water. If people consider

their livestock to be more important

than doing the laundry, then they

will distribute the available water

accordingly. Ensure that there is

enough water to meet people’s

priority needs with enough left over

to meet the priorities related to

effectively managing the emergency!

Table 9.2 suggests minimum water

quantities for non-domestic uses.

Step-by-step improvements

In the first phase of an emergency, it

may not be possible to meet all the

water needs of the community.

A staged-approach should be

adopted with initial efforts focused

on meeting survival needs (Figure

9.5). The service can be gradually be

improved with time as resources allow

(see Table 9.3).

Figure 9.4. Relationship between water collection journey time and domestic consumption

Use Guideline quantity

Health centres and hospitals 5 litres/out-patient; 40-60 litres/in-patient/day. Additional quantities

may be needed for laundry equipment, flushing toilets, etc.

Cholera centres 60 litres/patient/day; 15 litres/carer/day

Therapeutic feeding centres 30 litres/in-patient/day; 15 litres/carer/day

Operating theatre/maternity 100 litres / intervention

SARS isolation 100 litres / isolation

Viral Haemorrhagic Fever

isolation

300-400 litres / isolation

Schools 3 litres/pupil/day for drinking and hand washing (use for toilets not

included: see below)

Mosques 2-5 litres/person/day for washing and drinking

Public toilets 1-2 litres/user/day for hand washing; 2-8 litres/cubicle/day for toilet

cleaning

All flushing toilets 20-40 litres/user/day for conventional flushing toilets connected to a

sewer; 3-5 litres/user/day for pour-flush toilets

Livestock/day Cattle, horses, mules: 20-30 litres per head; goats, sheep, pigs: 10-

20 litres per head, Chickens: 10-20 litres per 100

Vegetable gardens 3-6 litres per square metre per day

Table 9.2. Guidelines for minimum emergency water quantities for non-domestic use

Source: Adapted from Sphere

Time – from initial

intervention

Quantity of water

(litres/person/day)

Maximum distance from

shelters to water points (km)

2 weeks to 1 month 5 1

1 to 3 months 10 1

3 to 6 months 15 (+) 0.5

Table 9.3. Suggested quantities of water, and distances of water points from shelters at

different stages of an emergency response

Source: Adapted from Sphere. Also see WHO, 2008. Essential environmental health standards

in health care. World Health Organization, Geneva. http://www.who.int/water_sanitation_health/

hygiene/settings/ehs_hc/en/

Figure 9.5. Meeting survival needs

Return trip travel time

(minutes)

Water

consumption

(Lpcd)

10 20 30 40 50 60

Further information

House, Sarah and Reed, Bob (2000) Emergency Water

Sources: Guidelines for selection and treatment,

WEDC, Loughborough University, UK.

http://wedc.lboro.ac.uk/publications/

The Sphere Project (2004) Humanitarian Charter and

Minimum Standards in Disaster Response. The

Sphere Project: Geneva, Switzerland.

http://www.sphereproject.org

U.S. Agency for International Development, Bureau for

Humanitarian Response, Office of Foreign Disaster

Assistance (OFDA) (1998) Field Operations Guide for

Disaster Assessment and Response

http://www.usaid.gov/our_work/humanitarian_

assistance/disaster_assistance/resources/index.

html#fog

How much water is needed in emergencies

Prepared for WHO by WEDC. Authors: Brian Reed and Bob Reed. Series Editor: Bob Reed.

Editorial contributions, design and illustrations by Rod Shaw

Line illustrations courtesy of WEDC / IFRC. Additional graphics by Ken Chatterton.

Water, Engineering and Development Centre Loughborough University Leicestershire LE11 3TU UK

T: +44 1509 222885 F: +44 1509 211079 E: [email protected] W: http://wedc.lboro.ac.uk

9.4

Water, Sanitation,

Hygiene and Health Unit

Avenue Appia 20

1211 Geneva 27

Switzerland

Telephone: + 41 22 791 2111

Telephone (direct): + 41 22 791 3555/3590

Fax (direct): + 41 22 791 4159

URL: www.who.int/water_sanitation_health

this publication. However, the published material is being distributed without warranty of any kind, either expressed or implied. The responsibility for the interpretation and

use of the material lies with the reader. In no event shall the World Health Organization be liable for damages arising from its use.

Box 9.2. A sample calculation

How much water is needed for a camp of 5,000 displaced people (including 1,000 primary

school age children), 25 relief agency staff, and 75 cows?

The camp has a mosque and a small health centre without patient facilities. Each family has

been provided with a pit latrine and most people use water for anal cleansing. A feeding

centre is currently provided but is expected to close once the health of the population has

stabilized. A primary school will be constructed at a later stage.

Decisions

• Water for crops will not be provided.

• Staff will be resident during the initial stages of the emergency but will be able to travel into

the camp at a later date and are not normally included in this calculation.

• Assume 10% wastage from spills, leaks and waste.

Phase 1: Survival supply (litres)

Domestic use: 5,000 x 7.5 = 37,500

Feeding centre (small children estimated number): 500 x 30 = 15,000

Carers: 500 x 15 = 7,500

Relief staff: 25 x 30 = 750

Health centre : (assume 250 visits per day): 250 x 5 = 1,250

Mosque (assume all adults visit daily): 3,000 x 2 = 6,000

Cattle: 75 x 20 = 1,500

Total : = 69,500

Add 10% leakage: = 6,950

Approximate litres per day: = 76,450

Phase 2: Long-term solution (litres)

Domestic use (assume population remains static): 5,000 x 15 = 75,000

Staff office (daily office use only): 25 x 5 = 125

School: 1,000 x 3 = 3,000

Health centre: 250 x 5 = 1,250

Mosque: 3,000 x 5 = 15,000

Cattle (allow for some growth in numbers): 100 x 30 = 3,000

Total = 97,375

Add 10% leakage = 9,737

Approximate litres per day: = 107,112

Calculating water demand

A large number of assumptions have

to be made to calculate the total water

requirements in an emergency. Often,

basic information is not available and

the situation changes very quickly. Box

9.2 shows how total water demand

can be estimated and the types of

assumption that have to be made.

Remember, it is only an estimate!

Demand can be much higher or lower

than estimated, so allow as much

flexibility as possible in the amount of

water you can actually provide.

Ensuring supply has an

impact

Providing water does not always mean

it will have the desired impact on, for

example, the protection of health.

Look at the entire water supply system

and identify weak points. Providing

more water to a tap stand will not

necessarily increase consumption

if it is too far away, or if people do

not have enough water containers.

Providing more water may cause

drainage problems if there are no

facilities for disposing of sullage.

Regularly check how much water

people are actually using; when and

where are they using it; and how they

are using it.