Cleaning up the home after a flood – developing
country situations
This leaflet has been put together to provide advice and background information on
cleaning up the home after floods. It also gives advice on post-flood decontamination
of drinking water sources and treatment of water for domestic use during the flood.
This advice sheet focuses on key issues for middle and lower income communities in
developing country situations. For more detailed information consult our other advice
sheet entitled “Coping with floods, cleaning up afterwards – and staying healthy”.
Background
Flooding is the most common type of natural disaster worldwide – 40% of all natural
disasters. Whilst the numbers of other types of natural disasters continue to decrease
the number of floods continues to rise.
Every year in South East Asia, hundreds of millions of people living in lowland riverline or coastal areas are affected by flooding.
Quite apart from the devastation caused by the Tsunami in South East Asia, many
countries in Asia, Africa and Latin America are regularly devastated by floods during
the monsoon season. In South East Asian countries such as India, Bangladesh,
Myanmar, Nepal, Laos, Vietnam etc. monsoon floods and cyclones are almost an
annual phenomena. The 1999 cyclone in Orissa (India) killed 10,000 people and
affected 10-15 million people. In Bangladesh the devastating floods of 1991 and
1998 affected more than 30 million people, and the death toll was 1,40,000. More
recent floods in China and Korea have made more than 2 million homeless.
Torrential rain and flooding hit the Dominican Republic and Haiti with drastic effects.
In Prague, in 2002, more than 35,000 people were evacuated from their homes when
the Vltava River burst its banks. In 2003, there was significant flooding in Florida and
Jamaica following the hurricanes which hit the area. In the UK five million people live
in places with a risk of flooding.
Cleaning up after a Flood.
Floods present obvious health risks including drowning, electrical shock and
starvation. Advice and fact sheets on what to do before a flood, once the flood arrives
and after a flood can be found on the Federal Emergency Management Agency
(FEMA) website http://www.fema.gov/. Floods can also bring the risk of epidemic
disease, which if not addressed appropriately can persist in the environment a long
time after the flooding has ceased. This is exacerbated in hot climates.
Flood water affecting the home or other property is likely to be heavily contaminated
with sewage and other organic material such as animal carcasses and, therefore, it
must be assumed that it is contaminated with human pathogens (germs). It may take
a long time to dry out after flooding, especially in humid climates, and moulds can
establish and grow on surfaces causing spoilage of items. Thorough cleaning and
disinfection is recommended on all surfaces affected. Ventilation is also important in
order to assist the drying process.
General guidelines when cleaning up are as follows:
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Protect yourself from floodwater and other possible sources of germs as much as
possible, taking care to cover open cuts and wounds on exposed skin.
Waterproof dressings, rubber gloves and a mask to cover the nose and mouth
are ideal if available. It is advisable to wear rubber boots in case there has been a
backflow of sewage into the house.
Do not let children play in floodwater and wash their hands frequently, particularly
before eating food.
As soon as possible, remove and bury any faecal material from humans or
animals to prevent spread of germs. The risk of spread of germs from residues of
faecal material can be reduced by application of concentrated bleach solution*.
This can also help reduce the infection risk to those involved in cleaning up the
area.
Food or drink suspected of being contaminated should be thrown away.
As soon as possible, transfer all refuse to secure plastic bags or other containers
to prevent the spread of germs until the refuse can be taken away.
Remove as much silt and water as possible from the home. Good ventilation and
heating of the home will speed up the drying process, and prevent mould growth
and reduce the risk of spread of germs.
Remove and discard contaminated household materials such as furnishings and
fittings that are damaged beyond repair e.g. wall coverings and rugs.
All hard surfaces should be hygienically cleaned either by cleaning followed by
disinfection or by using a disinfectant/cleaner**. Be particularly careful to
thoroughly disinfect surfaces that may come into contact with food, such as work
surfaces, food storage shelves, refrigerators etc. Areas where small children play
should also be carefully cleaned and disinfected. Allow all surfaces to dry
thoroughly – good ventilation and heating will speed up the drying process.
For areas where mould has already begun to develop, a concentrated solution of
bleach* may be used to kill the mould and whiten and remove the black stains
that the mould produces. When the surface is visually clean, clean again with a
fresh solution of bleach in order to kill any remaining non-visible mould spores.
Allow all surfaces to dry thoroughly.
For those items which are not irreparably damaged, but which cannot be washed
or dry-cleaned, such as mattresses, air dry them in the sun and then if there is no
risk of colour damage spray them thoroughly with a solution of bleach.
Bedding, clothing and other soft / fabric articles including children’s toys etc
should be laundered according to IFH guidelines***
Any item that comes into contact with food such as crockery, cutlery, utensils and
cooking equipment MUST be “hygienically cleaned”** before re-use. If an
adequate supply of hot water is available this can be done by detergent-based
cleaning followed by thorough rinsing. Otherwise the items should be cleaned
and then disinfected by soaking in a solution of bleach**.
Do not be tempted to salvage foodstuffs. Any food item that has been in contact
with floodwater should be regarded as contaminated and discarded. If it is not
possible to reach shops, eat canned food, provided that the can has not been
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punctured, corroded or damaged in any way and is not showing any signs of
bulging or leakage. It is recommended to thoroughly clean and then disinfect the
lid of the can with a solution of bleach to prevent any contaminants from entering
into the contents on opening. If the contents of the can have an unpleasant odour
or colour or if the food looks mushy and the liquid cloudy, dispose of the can in a
sealed plastic bag. NEVER even taste the food from cans that show any signs of
spoilage in order to avoid the risk of botulism poisoning
Never use untreated floodwater for drinking, food preparation and cooking.
Advice on treatment of water is given below.
* Concentrated bleach
In situations where concentrated bleach is required a solution containing not less
than 4.5% or 45,000ppm available chlorine should be used
**Hygienic cleaning of surfaces
Since flood water affecting the home or other property is quite likely to be
contaminated with sewage, animal faeces, refuse etc. it is important that all surfaces
are “hygienically cleaned” in order to get rid of germs as well as visible dirt. Hygienic
cleaning of surfaces can be achieved in a number of ways according to the extent of
the contamination and the facilities available:
 Cleaning using detergent (liquid or soap) and hot water. Detergent and hot
water cleaning can be used to produce a hygienically clean surface provided that
the surface is then thoroughly rinsed using clean (potable) running water.
Mechanical action using a cloth, sponge or brush to maximise removal of soil and
microbes is an important part of the process. Removal of soil by wiping with a
cloth without subsequent rinsing is not considered sufficient to achieve a surface
that is hygienic. Use of a contaminated cloth can actually spread pathogenic
organisms onto previously uncontaminated hands and hand and food contact
surfaces.
 Cleaning using soap or detergent and a disinfectant product. This process
should be used on large surfaces which cannot be rinsed or for situations where
an adequate supply of running water is not available.
- If the surface is heavily soiled, clean thoroughly to remove the visible soil
using a solution of detergent or soap. Using a clean cloth apply a solution of
bleach, diluted to 0.5% or 5000ppm available chlorine, to the surface. Since
disinfectants are inactivated to a greater or lesser extent by the presence of
soil, heavily soiled surfaces MUST be cleaned before application of a
disinfectant.
- If the surface is only “superficially“ dirty, it may be hygienically cleaned using
a combined bleach/cleaner containing 0.5% or 5000ppm available chlorine.
The solution should be applied with a clean cloth or via a spray bottle and the
surface then wiped. If necessary repeat the process until the surface appears
visibly clean.
Household bleach (both thick and thin bleach) for domestic use typically contains 4.5
to 5.0% available chlorine. Bleach/cleaner formulations (e.g. sprays) are formulated
to be used “neat” (i.e. without dilution). It is always advisable however to check he
label as concentrations and directions for use can vary from one formulation to
another.
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*** Hygienic cleaning of laundry
Laundry can be made hygienically clean by:
 washing at 40-60°C with an oxygen bleach-based product (check ingredients on
the package to look for “active oxygen bleach” content)
 washing at 60°C or above (using any product as the higher temperature kills
germs).
Washing at temperatures of 40°C or less with a non bleach product is considered to
carry a risk of inadequate decontamination.
Why use Bleach?
Bleach contains hypochlorite. It is highly effective against viruses, bacteria, yeast and
moulds. Bleach acts very quickly (within 1 minute) but longer times are required for
killing moulds and fungi. Bleach is also an excellent “cleaner” for the removal of
mould growth. Bear in mind that chlorine-based bleaches can damage and/or bleach
fabrics, carpets and soft furnishings. It can also corrode metal surfaces
Post flood decontamination of drinking water sources and treatment of
water for domestic use during the flood.
Decontamination of drinking water sources after the flood.
In rural areas such as those in South East Asian countries such as Myanmar,
Nepal, India, Bangladesh, Laos, Vietnam etc. many or most of the tube
wells/dug wells that serve as sources for domestic water supply (both for private
and public supply) become grossly contaminated with faecal matter during the
floods. Unless they are thoroughly decontaminated (super chlorination), during
the post flood situation, water borne infections such as diarrhoea, dysentery,
typhoid, infectious hepatitis etc. are likely to occur. Super Chlorination of these
contaminated sources can be achieved by adding chlorine to the water (in the
form of bleaching powder (calcium hypochlorite) or bleach solution) and
ensuring a contact period of 24 hours. The final concentration of chlorine in the
water should be 25-50mgm/l available chlorine. For further details on how to
prepare and dilute chlorine solutions consult the WHO website:
http://www.who.int/water_sanitation_health/publications/2011/tech_note5/en/ind
ex1.html
Treating water in the home to make it safe for drinking
During the flood, supply of safe and potable water to the isolated population is a
serious problem. Point-of-use treatment of the turbid floodwater to make it drinkable
can be undertaken with a simple technique of coagulation, flocculation and
disinfection.
Pretreatment of turbid water
Turbid water should be filtered through a cotton cloth to remove any solid materials,
treated with alum and bleaching powder, stored for at least 2h and then decanted or
filtered through a clean cloth. For pre-treatment add 10g alum and 5g lime per 100l of
turbid water.
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Treatment to eliminate pathogens
1.
Chemical disinfection
Where chlorine or iodine tablets are available, they should be used as directed
by the manufacturer. Alternatively water should be disinfected with hypochlorite
in the form of bleaching powder or hypochlorite solution for 30 mins. The final
concentration of chlorine should be 0.5-1mgm/l available chlorine after 30 mins.
The amount of chlorine needed depends mainly on the concentration of organic
matter in the water and should ideally be determined for each situation using a
test kit. For details on preparing chlorine solutions consult:
http://www.who.int/water_sanitation_health/publications/2011/tech_note5/en/ind
ex1.html
For disinfection with iodine a concentration of 3.7 mg/l, contact time 10 mins, is
required (6.3 mg/l if virucidal contamination is suspected).
2.
Boiling
Bringing water to a rolling boil will kill pathogens effectively, except at high
altitudes. A holding period of 3-5 mins will ensure that water is safe, except in
situations where contamination with spore-forming bacteria, fungal or protozoal
cysts or hepatitis virus is suspected, in which case 10 mins is advised.
Other methods for disinfection of household water are available including filtration,
solar disinfection, UV irradiation and combined flocculation/disinfection systems.
Further details of these methods can be obtained from the IFH teaching/self learning
resource on home hygiene.
Advice on such treatment of water can also be obtained from:
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Emergency treatment of drinking water at point-of-use. WHO technical note for
emergencies No. 5
http://www.who.int/water_sanitation_health/publications/2011/tech_note5/en/inde
x1.html
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Household Water Treatment and Safe Storage Following Emergencies and
Disasters.
http://www.who.int/water_sanitation_health/emergencies/tsunamiguidelines/en/
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Household water treatment and safe storage
http://www.who.int/household_water/en/
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Safe water in the home: household water treatment and safe storage
http://www.ifh-homehygiene.org/factsheet/safe-water-home-household-watertreatment-and-safe-storage
Useful sources of Information.
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IFH teaching/self learning resource on home hygiene: Home Hygiene in
Developing Countries: Prevention of Infection in the Home and Peridomestic
Setting. A training resource for teachers and community health professionals
in developing countries. International Scientific Forum on Home Hygiene.
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Available
from:
www.ifh-homehygiene.org/best-practice-training/homehygiene-developing-countries-prevention-infection-home-and-peri-domestic
WHO Technical notes for emergencies
http://www.who.int/water_sanitation_health/hygiene/envsan/technotes/en/inde
x.html. These four-page illustrated notes have been prepared to assist those
working immediately or shortly after an emergency to plan appropriate
responses to the urgent and medium-term water and sanitation needs of
affected populations. The notes are relevant to a wide range or emergency
situations, including both natural and conflict-induced disasters.
Storm-Related Mortality by Center for Disease Control and Prevention (CDC).
www.bt.cdc.gov/disasters/floods.
UNICEF water and sanitation in emergencies.
http://www.unicef.org/wash/index_emergency.html
Last updated 2015
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