Dealing With Infection Risks In
The Home After A Flood
Advice Sheet issued by the International Scientific Forum on Home Hygiene
This resource has been put together to provide advice and background
information on cleaning up the home and post-flood decontamination of
drinking water sources after floods. It also gives advice on treatment
of water for domestic use during the flood.
A global problem
Flooding is the most common type of natural disaster worldwide, comprising
forty percent of all
While the numbers of other types of natural disasters continue to decrease,
the number of floods continues to rise.
year in South East Asia, hundreds of millions of people living in lowland
river-line or coastal areas are affected by flooding. In the UK five million
people live in places with a risk of flooding.
apart from the devastation caused by the Tsunami in South East Asia, many
countries around the world are often
devastated by floods, particularly during the monsoon time:
►In South East Asian countries
like India, Bangladesh, Myanmar, Nepal, Laos, Vietnam etc monsoon floods &
cyclones are almost annual phenomena
►The 1999 cyclone in Orissa
(India) killed 10,000 people and affected 10-15 million people.
►In Bangladesh the devastating
flood of 1991 & 1998 affected more than 30 million people, and the death
►The recent floods in China &
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
►In 2003, there was
significant flooding in Florida and Jamaica following the hurricanes which
hit the area.
Health risks 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 FEMA website.
►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. In the rural areas such as those in South
East Asian countries like Myanmar, Nepal, India, Bangladesh, Laos, Vietnam
etc many or most of the tube wells/Dug wells which serve as sources for
domestic water supply (both for private as also for public supply) get
grossly contaminated with faecal matters during the floods. Unless they
are thoroughly decontaminated (super chlorination) during the post flood
situation, water borne infections like diarrhea, dysentery, typhoid,
infectious hepatitis etc are likely to occur.
3. General guidelines for
cleaning up and decontaminating water sources after a flood
►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.
cleaning and disinfection is recommended on all surfaces affected.
Ventilation is also important in order to assist the drying process.
►Protect yourself from
floodwater and other possible sources of germs as much as possible,
particularly covering open cuts and
wounds on exposed skin.
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.
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.
►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, prevent mould growth
and reduce the risk of spread of germs.
►Remove and discard
contaminated household materials such as soft furnishings and fittings
that are damaged beyond repair eg.
►Wall coverings, rugs.
those items which are not irreparably damaged, but which cannot be washed
or dry cleaned such as mattresses or upholstered
►Furniture, air dry them in
the sun and then, if there is no risk of colour damage, spray them thoroughly with a solution of bleach.
►Steam clean all carpeting if
►Bedding, clothing and other
soft / fabric articles including children’s toys etc should be laundered
washing at 40-60°C with a bleach-based product (check ingredients on the package), or
washing at 60°C or above (using any product as the higher temperature kills germs).
►All hard surfaces should be
hygienically cleaned either by cleaning followed by disinfection or by
using a cleaner/disinfectant**.
particularly careful to thoroughly disinfect surfaces that may come into
contact with food, such as work surfaces, pantry shelves, refrigerators etc.
where small children play should also be carefully cleaned and
disinfected with bleach. Allow all surfaces to dry thoroughly good ventilation and heating will speed up the drying
►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.
►Any item that comes into contact with food such as crockery, cutlery,
utensils and cooking equipment MUST be “hygienically cleaned
►If an adequate supply of hot water is available this can be done by
detergent-based cleaning followed by thorough rinsing. Otherwise
items should be cleaned and then disinfected by soaking in a solution of
►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 punctured, corroded or damaged in any way and is not showing any
signs of bulging or leakage.
►Never use untreated
floodwater for drinking, food preparation and cooking. Point of use
treatment of the turbid floodwater to make it drinkable
be undertaken with a simple technique of coagulation, flocculation &
►Before treatment, remove any solid materials and filter through a cotton
►Water sources must be
thoroughly decontaminated to avoid the risk of water borne infections with Super Chlorination.
This 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
4. Useful sources of information.
a) On the IFH website
For comprehensive guidelines on how, when and where, hygiene should be
applied in the home to prevent the spread
of infectious disease:
Guidelines for prevention
of infection and cross-infection in the domestic environment: Focus on
home hygiene issues in developing countries:
selection of suitable hygiene procedures for use in the domestic
b) On the Internet
Bleach contains hypochlorite. It is highly effective against viruses,
bacteria, yeast and moulds. Bleach acts very quickly (within 1 minute) but
are required for killing moulds and fungi. Bleach is an excellent “cleaner”
for even the toughest soils, and for the removal of mould growth. Bear in
that chlorine-based bleaches can damage and/or bleach fabrics, carpets,
soft furnishings and can corrode metal surfaces. 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
It is always advisable however to check the label as concentrations and
directions for use can vary from one formulation to another.
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
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
“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 maximize 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
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.