According to the Environment Agency about 5 million people, in 2 million properties, live in flood risk areas in England and Wales. Floods are one of the most common and widespread of all natural disasters and are growing in frequency and severity, possibly an adverse consequence of global warming. Flooding can have a devastating impact on your property and surrounding area. It is important that during a flood you are able to be in a place that is safe for you, your family or work colleagues.  

Assessing the level of risk is not easy, particularly when insurance companies and others factor in things such as damage from the sea, rivers, drainage channels, surface water run-off, drain pipes, ground water, etc. It is important to get this level of risk right, because the cause dictates the remedy, for example if the problem is surface water run-off, good old-fashioned sand-bags may suffice. However, if the risk is from, say, the River Severn flooding, more robust measures will probably be needed.

What is the first priority to consider?
If your property is vulnerable to flooding, the first priority is to undertake flood protection works. You may not be able to stop flood water entering, but you will be able to minimise the damage that will be caused. There are many websites that provide advice on flooding, but some of the information can be quite technical. A local chartered building surveyor will be able to help you.  Do note that if you expect flood water to be deeper than 600mm there is an increased risk of structural damage to the walls. Please remember, flood water is often contaminated.

Questions to consider:
What is the likely source of a flood?
How often will a flood occur?
Has the property or surrounding land and gardens ever flooded in the past?
Have neighbouring properties ever flooded?
Is the property on a floodplain?
Has the property been issued with a flood warning?
Is the property close to surface water drainage, ditch or a stream that could overflow?
Is the property in a hollow or low-lying area?
Is the property protected by river or coastal defences?
What is the likely maximum depth?
How long is it likely to last?

This may seem a little dramatic but this is a worthwhile exercise for both the individual and an organisation. An exercise such as this can help to identify risks and mitigate the damage and the inevitable misery that accompanies flooding.

Identify the routes via which flood water may enter your property:
All sorts of gaps and cracks exist in most buildings. Many can be sealed permanently, while some, such as air-bricks, can be temporarily protected when a flood is imminent.
Your ground floor WC may become a fountain, jetting foul smelling water into your home or place of work - this is preventable.
Walls, windows and doors: These can be made more resilient, but do remember that deep flood water will exert enormous pressure.
Simple expedients may be to re-plaster ground floor walls if they are currently covered with gypsum plaster (which takes water like blotting paper).
Flood boards can be a very effective way of excluding flood water. There are many proprietary systems on the market which work well, and could give you peace of mind, if you leave the property vacant for any length of time. But remember that a holistic view of the problem needs to be taken, e.g. don't forget those air-bricks before trusting flood boards to do everything.

When flooding strikes
The first thing to do is to check the flood warnings by listening to the radio, TV reports or phoning the Floodline on 0845 988 1188. Keep valuable items above likely flooding levels: This includes your insurance documents as well as those prized and irreplaceable personal belongings. If possible, keep copies of insurance documents in another location (with family, friends, lawyer etc). This advice applies to all properties, even those that have not experienced flooding before - there is always the first time. Flooding can happen so swiftly that there may not be time to take even these simple measures. The Association of British Insurers website gives good post-flood advice on insurance issues.

A check list of things to consider during a flood:
As mentioned, move valuables and other items to safety.
Make sure your property is well ventilated.
If possible, put sandbags in place around your property.
Unplug electrical items and store them away, preferably in a high place.
Be prepared to turn off gas and electricity.
Utilise the day as much as possible to get things done.
During flooding, there is the risk of electricity failure.
Co-operate with emergency services and local authorities at all times as you may need to be evacuated and taken to a rest centre or shelter.

Stay safe - floods are dangerous and can kill, don't try to walk or drive through floodwater. There are many hazards that you may not be able to see such as manhole covers, stones etc. Swimming through floodwater should never be attempted as the speed of the water flow is difficult to judge and you could be hurt by objects in the water.
Don't walk on sea defences, riverbanks or cross river bridges. In extreme situations they may collapse or you may be swept off by large waves.
When the water begins receding, plan the future steps to rehabilitation and restoration carefully.
Contact your insurance company who will be able to advise you on what to do next. Your insurance company may require that significant repair cost estimates are supported by technical reports confirming the nature and extent of damage. This can be provided by a chartered surveyor experienced in property inspection.

Services: All gas and electrical appliances that have come into contact with floodwater must be inspected by a qualified engineer before they are re-used. There are some straightforward ways of minimising the damage to services. For example, if the property is at medium risk of flooding, it might be worth raising all electrical cables to first floor height, with drops down to sockets at hip-level. Similarly, incoming electrics and consumer boards should be sited above flood level. The same applies to the incoming gas main and meter, not forgetting to seal around all service entry pipes, ducts, conduits, etc. Your gas supplier may be able to make provision for purging gas supply pipes through the installation of appropriate drain points. For those ground floor WC's, a one-way valve may be the answer.

Don't rush the recovery and drying-out period. This may seem harsh, but above all allow the property to dry out fully. Being in a hurry to redecorate too soon can aggravate all sorts of problems e.g. causing moisture to become trapped inside the walls. If you must redecorate, use porous materials, not vinyl. If you notice floor slabs have cracked or other related structural defect take professional advice from a chartered surveyor. This type of defect could be associated with the enormous upward pressure that ground water can exert. The flood may have swept away your boundary fences etc and this might, unfortunately, lead to neighbourly disputes when it comes to reinstatement. Professional advice from a chartered surveyor will help overcome such issues. The RICS has produced specific post flood advice on boundary reinstatement.

Major repairs may require access on or over the land of a neighbour and due to a variety of reasons one party may be reluctant to grant the necessary access to facilitate the repairs. Legal access rights via either the Party Wall etc Act 1996 or Access to Neighbouring Land Act 1992 may provide assistance when cross boundary repair work is required. This process may require the assistance of a chartered surveyor to administer the procedure via expert reports for a Court Access Order or service of formal Notices and negotiation of Award in the party wall context.

The nature and extent of damage after a major flood can be significant, with structural damage to property. This may be created during water rushes that have been known to have enough energy to lift cars, fell trees and move water at force resulting in associated impact damage. The nature and extent of serious damage may require complex structural repair to reinstate the property. Therefore, the repairs could be complex, requiring professionally supervised design and construction techniques which can all be undertaken by a chartered surveyor. Repair costs and building works may lead to reinstatement projects involving significant sums of money, to the extent that normal financial management of the contractor should be administered via a formal contract with recorded cost control. Project management techniques to coordinate various trades and contractors to ensure a swift return are easily administered by chartered surveyors experienced in construction to a post flood situation.