Flood management

Find out if your area is at risk of flooding and how you can prepare.

Areas at risk of flooding

The Thames and its tributaries are at most risk of flooding during heavy rain and at high tide. Areas most likely to be affected in the borough are New Cross, Deptford, central Lewisham, and low-lying areas around the A21.

While the Thames Barrier is designed to help prevent flooding due to high tides, we have also made substantial landscaping improvements to reduce the risk of flooding by increasing the capacity of the borough’s waterways and rivers:

find out if your area is at risk of flooding

Preparations and precautions you can take

sign up online to the Environment Agency’s free alert system Floodline Warnings Direct or by calling 0845 988 1188 – you can select to receive warnings by phone, text, email, fax or pager
know how to turn off your gas, electricity and water supplies
check your buildings and contents insurance policies to see what cover they provide for flood damage
make a plan for how to deal with a flood should it happen – think about what you would want to move to safety
keep flood waters out by buying sandbags and covers for air bricks and other vents. It is not our responsibility to provide you with sandbags, but they are available from builders' merchants.
buy flood-proof products; a comprehensive list of these can be found in The Blue Pages directory on the National Flood Forum’s website.

You can find more advice on Protecting your Property from Flooding on gov.uk.

Find out more about flooding on the Environment Agency's website.

Flood prevention responsibilities of property owners

It's your responsibility, as a homeowner or business, to look after your property. This includes protecting it from flooding.

There are a number of organisations responsible for flood prevention.If you are a property owner, you also have responsibility for flood risk management .

Organisations responsible for flood risk management

What the Council's doing to manage flood risk

Taking action on flood risk is vital to protect our most vulnerable communities. It also creates the opportunity for wider benefits. The borough’s rivers are a natural asset enjoyed by residents and nature alike.

Our flood risk management strategy sets out the Council’s plans to work with partners nationally, regionally and locally to create a greener and safer Lewisham.

We're taking long-term action to help protect homes, businesses and open spaces from flooding. By reducing the causes of flooding, it also prevents pollution from entering our rivers, keeps streets cooler in summer, protects local wildlife, and creates greener, more pleasant neighbourhoods.

Projects include:

improving drainage systems to manage heavy rainfall
restoring riverbanks and creating natural flood storage areas
de-paving streets and other hard surfaces to absorb more rainwater, including using raingardens, permeable paving, and other types of Sustainable Drainage Systems (SuDS)
planting more trees, adding more green spaces, and improving existing spaces
working with the Environment Agency, Thames Water, local community groups and others
working as part of the Ravensbourne Catchment Partnership to deliver the Ravensbourne Catchment Action Plan
installing new air quality and water monitoring stations across the borough
supporting landowners help manage flooding directly by signposting them to Lewisham’s SuDS Design and Evaluation Guide

Flood risk management responsibilities

Landowners, homeowners and businesses

Know your responsibilities

If you're a landowner, homeowner or business, you're responsible for protecting your property from flooding; and rehousing tenants if your property becomes uninhabitable. If a watercourse (stream, river, ditch) runs through or borders your property, you're a 'riparian owner' and must:

keep water flowing and clear blockages
maintain banks, beds, and flood defences
maintain structures like culverts, weirs and mill gates
allow natural water flow from upstream to downstream

If a watercourse is the boundary between properties, each owner is normally responsible up to the centre of the watercourse.

Need to do work in or next to water?

If your property's next to a watercourse and you're considering development, see the River Corridors Improvement Plan SPD and our Biodiversity Net Gain (BNG) page.

You’ll also need permission. Download Living on the Edge from the Environment Agency.

Get prepared:

check your home or business for flood risk and sign up for free Environment Agency flood alerts to get warnings by phone, text, or email
get flood protection tips and advice: Floodline 0345 988 1188
see Protecting your home or business

Get insured

You can get:

buildings insurance - to cover flood damage to buildings
contents insurance - to cover damage to items, for example stock
business interruption insurance - to cover running costs or losses, for example salaries or loss of profit

Get advice from the National Flood Forum on insurance for small businesses.

Flood Re works with insurers behind the scenes. When you buy home insurance cover, your insurer can choose to pass the flood risk element of your policy to Flood Re for a fixed price. If you make a valid claim for flooding, your insurer will pay the claim. Later on, Flood Re will reimburse that insurer from the Flood Re fund. In short, you buy home insurance in the usual way. Flood Re cover the flood risk and that helps to keep your premiums down. You can check your eligibility on the Flood Re website.

Tenants

If you're renting there's plenty you can do to prevent and prepare for flooding (see Protecting your home or business). You’re also responsible for notifying your landlord if there's a problem.

ask your landlord what insurance they have as it may not cover your personal items
if their insurance does not cover your personal items, you can get contents insurance
read the How to rent guide by the Ministry of Housing, Communities and Local Government, for more information about flooding and insurance

If your home becomes uninhabitable due to flooding, your Landlord is responsible for rehousing you. If they refuse and you are at risk of homelessness, contact the homelessness prevention service.

Lewisham Council responsibilities

The Council are responsible for managing the risk of flooding from:

surface water - water flowing over the ground during and after rainfall
groundwater - when water comes up from the ground
ordinary watercourses - small watercourses and ditches
public drains on public roads (except emergency/red routes managed by TfL)

When significant flooding events happen, we:

investigate the event
coordinate an emergency response

Our other responsibilities include:

publishing and delivering Lewisham’s Local Flood Risk Management Strategy
planning and delivering flood prevention works#
keeping a register of assets that have a significant impact on flood risk
consulting and advising on surface water drainage plans for developments
approving sustainable drainage systems (SuDS) for new developments
requiring developers to assess and reduce flood risks in planning applications
protecting structures that help prevent flooding
identifying third party features and assets which contribute to flood risk and notifying owners

Environment Agency responsibilities

manages flooding from rivers, reservoirs, estuaries and the sea
protects important flood defences. Structures that help manage flooding cannot be changed or removed without their permission
for advice during floods, contact Floodline | 0345 988 1188

Thames Water responsibilities

fixes burst water mains and leaks
provides, manages, and maintains sewers and drainage systems
manages sewer flooding caused by rainwater
to report a burst water main or public sewer flooding, call 0800 714 614

Transport for London responsibilities

manages drainage on red routes (main roads)
report flooding on red routes online to TfL or call 0343 222 1234

Further guidance

Lewisham's Flood Risk Management Strategy

Environment Agency

oversees the management of all sources of flooding
manages the risk of flooding from main rivers, reservoirs, estuaries and the sea
powers to designate existing structures and features as flood risk management assets, meaning cannot be altered, removed, or replaced without the consent of the designating authority.

Thames Water

manages flood risks arising from water and foul or combined sewer systems where the flooding is a result of rainwater affecting the sewer system
provides and maintains public sewers so that the areas it is responsible for are effectively drained
repairs water mains pipes if a water main bursts.

The Council

We are the lead local flood authority for the borough and have the following responsibilities:

leading the coordination of local flood risk management in Lewisham with the other organisations involved
developing a local flood risk management strategy
statutory powers to carry out works to manage flood risk, consistent with the local flood risk management strategy
identifying and managing the flood risk from surface runoff, groundwater and small watercourses and ditches, known as ordinary watercourses
investigating significant flooding events
managing ordinary watercourse activities
maintaining a register of flood risk assets
designating assets or features considered to affect the flood risk from surface runoff and groundwater
approval of sustainable drainage systems (SuDS)
designate third party assets or features that affect flood risk and give notice to owners that they have been so designated.

We also have responsibilities for flooding in our role as the highway authority:

to maintain the public highway network, excluding red routes which are managed by Transport for London
to ensure highways are drained of surface water and, where necessary, maintain all drainage systems.

Please bear in mind that it is natural, after very heavy rainfall, for the gullies and sewers to take a few hours to clear the water that has fallen on the road, but if the flooding on one of our roads hasn’t subsided you can report this using our online form or by contacting the Council switchboard which is available 24/7 at 0208 314 6000.

As the local planning authority, we require developers in certain situations to identify and mitigate the risk of flooding to their proposed development and provide this information as part of the planning application process This requirement is underpinned by a strategic flood risk assessment which forms part of the evidence base for the Local Development Framework.

Transport for London

as the highway authority for red routes, they have a duty to ensure highways are drained of surface water - report flooding incidents on their roads
they are also responsible for maintaining all drainage systems on red routes

Flood reinsurance

Unlike other reinsurance companies it is a not-for-profit fund, owned and managed by the insurance industry, and it has been designed to address the specific issue of flood risk.

You don’t need to do anything different when buying your home insurance to access this scheme. You can buy your home insurance in whatever way most suits you. When the cost of the flood risk part of your policy goes above a certain level the insurer may place that part of the policy with Flood Re but you don’t need to be involved with this.

If a flooding incident happens, you only deal directly with your insurer to process and agree the claim. If the insurer accesses Flood Re support to meet part of the costs they will do this as part of administering the claim:

find out more about Flood Re

Published on: 30/07/2026