How to prepare for flash flooding
The Mayor of London, Sadiq Khan wants to make sure Londoners are aware of the risk of flash flooding in the capital and what they need to do to be prepared.
The risk of severe flash flooding is higher during the summer months but can occur any time of the year. Here’s what you need to do to be prepared.
In summer 2021, London was hit by severe flash flooding. The rain caused damage and disruption to homes and businesses across the city. Many Londoners had to stay elsewhere as their homes were flooded with stormwater and sewage.
The floods were devastating for many Londoners and whilst work is underway to reduce the impact, we cannot entirely prevent it. As the climate changes, we expect severe flooding to happen more frequently in our city.
Flash flooding can happen anywhere and the impact may be worse if you live in a basement property. This information will help you prepare for flash floods.
What you need to do to be prepared
- Sign up to the Met Office weather warnings.
- Put your valuables and important documents on a high shelf to protect them from water damage. Floods can destroy anything. Don't underestimate how important your possessions are to you. For example, family photographs may not be very expensive but they can be irreplaceable if they're destroyed by flood water. Think about moving items with sentimental value, as well as items you've spent a lot of money on.
- Learn how to turn off your water, gas and electricity supply. You may need to do this if you are flooded and it is safe to do so. The location of water stopcocks, gas shut-off valves and electrical master switches varies between properties. The gas shut-off valve is usually beside the meter. The mains electricity cut-off is usually a big red switch on your fuse box. If you can’t find your water stopcock, ask someone with practical experience or a plumber to help you.
- Check your household building or contents insurance covers flooding. If you don’t have any, FloodRe may be able to help.
- Create a list of useful contact numbers such as your insurance company, landlord, housing association and local council and save these in your phone. You can use your postcode to find your local council.
- Check drains outside your home and on your street are clear. As a homeowner you have a duty to clear the drains within your property boundary. If you are renter speak to your landlord or housing association. Report any street drainage issues through your council by phone, their online reporting system or at Fix My Street or Love Clean Streets. If you think you have a blockage within your drains or sewer, you could contact a plumber, WaterSafe have a directory of approved plumbers. Thames Water provide more information on blockages including homeowner responsibilities.
- Prepare a flood kit with any items you must have if you need to leave home including; medicine, warm/waterproof clothing, a phone charger, ID/essential documents and a torch. Find out how to prepare a flood kit.
What you need to do during flooding
If it floods, you should:
Act
- If water starts to enter your home, move yourself, your family and pets away from danger. If you live in a basement or ground floor flat, you could move to a neighbour’s flat on a higher level. Turn off electricity, gas and water if safe to do so. Do not drive through flood waters, just one foot / 30cm of water can be enough to move a car and beneath the water may be hidden hazards. Floodwater is hazardous and could contain chemicals and waste – do not allow children or pets to play in it.
Survive
- Call 999 if there is an immediate threat to life. Emergency services can help if you need to evacuate your home.
- Your local council will have more instructions on what to do and where to go in an emergency including possible temporary emergency shelter locations / emergency accommodation. Your council will have an in hours and out-of-hours number for emergencies. Find your local council and search 'Emergencies and Out of Hours Contacts’on the Council website, for details of their emergency contact numbers.
- If you are asked to leave your home, make sure you take your medication and if possible any medical equipment you need. Remember to tell family, friends and carers where you are going and if you are in receipt of a care package, please let your provider know where you have gone.
Lend a hand
- Check on vulnerable neighbours if it’s safe to do so.
What to do after a flood
Being flooded is extremely stressful but there are helpful tips on what to in the immediate aftermath of a flood and how to be more flood resilient in the longer term:
- Do not re-enter a flooded area until you are advised it is safe to do so.
- Do not enter a property that has been flooded unless you are sure it is structurally safe – if in doubt it should be professionally checked
- Do not turn on your electricity or gas supplies until they have been checked by a qualified electrician/ engineer.
- Be aware of gas leaks – do not smoke or use open flames
The Environment Agency provides useful information on how to recover after a flood.
See also the Fire Brigade advice.
This includes advice on:
- Contacting your insurance company
- Checking if you can return home
- Cleaning and repairing your home
- Protecting your property from future floods
- Staying healthy
- Getting help and emotional support
- Applying for financial aid
Get emotional support
Having a flooded home is very stressful. If someone has concerns about their own or others’ mental health, they can visit their GP, or call NHS 111, who can help identify further sources of support.
NHS One You guidance also has advice on how to deal with stress or anxiety as well as information about where one can access further support.
NHS Choices is a good source of local health information, including local mental health services.
Helplines, such as Samaritans, can provide support to anyone in emotional distress or struggling to cope. The Samaritans free helpline is available 24 hours a day on 116123. A small proportion of people may require access to specialist mental healthcare. This can be accessed through GPs, or by self-referring to a local Improving Access to Psychological Therapies (IAPT) Service.
Public Health England offers a guide to mental wellbeing after a flood. See Appendix 3 in particular.
Protecting your property from future floods
You can never eliminate the risk of flooding entirely, but you can reduce the risk of water getting in to your home or business and reduce its impact if it does get in. The techniques come under different names, including Property Level Resilience (PLR), Property Flood Resilience (PFR) and Property Level Protection (PLP).
There are steps you can take to protect your property from future floods. Blue Pages provides a directory of property flood products and services to help reduce the risk of flooding to your home. This includes sealable air bricks, flood doors, demountable flood barriers and flood boards. See also the National Flood Forum pages on protecting your property. You may also be eligible for funding to help install property resilience measures through the Build Back Better scheme.
DID YOU KNOW: Property owners are responsible for looking after their home(s) including protecting them from flooding and drainage issues within their property boundary. If you are a renter speak to your landlord or housing association about better protecting you from flooding.
Useful information
Flash flooding (also known as surface water or sewer flooding) can happen when very heavy rain falls on hard surfaces overwhelming drainage and sewers. This sort of flooding is difficult to predict, it often happens quickly with fast flowing water that could pose a risk to life. It is also more likely to happen during intense summer storms but can occur anytime of year. The likelihood of flooding remains low for most basement properties, but where it does occur, damage and risk to life can be serious.
- For emergencies such as serious illness, injury and risk to life, call 999: fire, ambulance and police services
- If your toilet, sink or bath is flooding (e.g. if wastewater or raw sewage is coming up through your toilet, sink or bath), call Thames Water: 0800 316 9800
- Inform your council of flooding coming from outside your property e.g. from the road or pavement. First, find your local council, then find contact information for the right team by searching for ‘flood’ or ‘flooding’ through the council website.
- For general advice, call the Environment Agency’s 24-hour floodline: 0345 988 1188
- The National Flood Forum has a helpline that provides general support before, during and after a flood on issues including insurance, home re-instatement and home resilience. Contact the National Flood Forum charity: 01299 403 055.
- To find an insurer, try FloodRe.
- If you are a renter add the number of your landlord, housing officer or housing association call out number to your phone. Inform your landlord/housing association if your home has flooded and needs repairs.
DID YOU KNOW: having insurance is important in case your home and belongings are damaged or destroyed during a flood. Have you checked your building or contents insurance covers flood damage?
You can also do your bit to help reduce the risk of flooding, encourage wildlife and support your wellbeing by changing just a part of your garden from grey to green. You can start small, even if you don’t have a garden of your own or you could join up with your community to run a community depaving project. If you already have a front garden keep it green. Paving over front gardens creates more impermeable surfaces which increase the risk of flooding. The Mayor is currently greening London and reducing flood risk through his green space funding programmes. This includes the green and resilient spaces programme supporting large-scale innovative enhancements to green and blue spaces and the Grow Back Greener Fund which supports community projects that will improve access to green space and help us adapt to climate change.
Whilst the Mayor has no formal powers related to flooding in London he convened those with legal duties for surface water flooding (boroughs, the Environment Agency, water companies) in a series of roundtable meetings to support a more coordinated approach, help minimise risk and better prepare Londoners and to review London’s emergency response arrangements to these incidents and the longer-term challenges of prevention and adaptation to surface water flooding.
Since the flooding in summer 2021, the London Resilience Forum has prepared a multi-agency rapid debrief on the incidents with 30 recommendations for the London Resilience Partnership to inform and improve future emergency response arrangements.
The address the longer-term challenges of adaptation, the roundtable established a task and finish group chaired by London Councils and the Environment Agency. The group looked at issues around who owns and manages flood risk, funding shortfalls for surface water flooding measures, availability of data and evidence to boroughs on current and future asset resilience and promoting community or household resilience. The group has recommended that a surface water flooding strategy be produced for London for the first time and a specific workstream to identify vulnerable basements.
A new governance group has been formed by key agencies with responsibility for managing surface water flooding to better manage surface water flooding in London. The group will ensure a more strategic and consistent approach to resolve some of the issues identified by the Mayor’s flooding roundtable. The Surface water flooding strategic governance group will oversee the development of the London Surface Water Flooding Strategy alongside other more immediate measures to help reduce London’s risk to surface water flooding.
Find out more about the work of the Mayor on the flooding pages.
The management of surface water flood risk (or flash flooding) in London is dispersed among a range of organisations with different responsibilities and accountabilities.
The Flood and Water Management Act specifies that surface water flooding is the responsibility of local authorities, designated as Lead Local Flood Authorities (LLFAs). In London this means there are 33 responsible authorities, one for each London borough and the City of London. There is no single responsible authority or agency bringing together the work of the individual LLFAs into a holistic picture for London.
The Department for Environment, Food and Rural Affairs (Defra) in Government is the policy lead for flood and coastal erosion risk management in England. New or revised policies are prepared with other parts of government such as the Treasury, the Cabinet Office (for emergency response planning) and the Department for Levelling Up, Housing and Communities (for land use and planning policy). These national policies are then delivered by Risk Management Authorities (RMAs). The RMAs relevant to London are:
- Environment Agency
- Lead Local Flood Authorities
- Water and sewerage companies
- Highways authorities.
Flooding is a complex hazard where multiple sources often interact, for example surface water, sewer and river flooding. It requires coordination between different Risk Management Authorities.
The Environment Agency officially has the strategic overview responsibility for all types of flood risk and works closely with Lead Local Flood Authorities, who are responsible for surface water and other RMAs in order to manage the risk. In the event of surface water flooding the Environment Agency will support partners in responding to this if resources are not needed for fluvial (river) or tidal flood response.
Water companies are responsible for managing public sewers. In London, Thames Water provides the drainage services and manages London’s sewer network and wastewater treatment facilities.
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