Commercial properties at higher risk of flooding due to history

The flood risk for commercial properties in the UK is significantly higher than for real estate in general due to historical reasons.

According to the FloodFlash Commercial Risk Report 2021, 26% of commercial property in the UK has at least some level of risk of flooding compared to 14% for all property. Historical access to waterways has meant a lot of commercial properties are built near water sources. Furthermore, low-lying land is used for large warehouses and sports grounds, increasing the flood risk for these buildings.

Of all commercial properties, 18% have a “significant risk” defined as being in a 75 year flood zone. In other words, these properties are likely to flood at least once every 75 years. Over 25 years the chance of a flood is approximately 1 in 3.

Surface water flooding is the biggest threat to property and puts 249,956 British commercial properties at risk. This type of flooding is driven by the collection of intense, localised rainfall and may occur in areas which are remote from any rivers or other water sources.

Of all commercial properties at risk, 53% are in the retail or industrial sectors. Retail or manufacturing make up 32% and 21% of all commercial properties at risk respectively. They are followed by offices (11%), general use (10%) and utilities (6%).

The worst recorded floods for British businesses occurred in 1947, 1953 and 2007.

  • Following an iron winter and extraordinary snowfall, a thaw began on March 7, 1947, combined with an inch of rain in a few hours. The rainwater could not soak into the still icy ground and snowmelt followed rapidly, causing big rivers to rise by a foot an hour. More than 100,000 properties were damaged. The floods peaked after a week and took another 10 days to subside completely, leaving immediate damage estimated by Clement Attlee's Labour government at £12m (£300m at current values). The final cost was between £3bn and £4.5bn.

  • Dubbed the worst natural disaster Britain experienced during the 20th century, the 1953’s ‘Big Flood’ was caused by a huge tidal surge that devastated low-lying housing of England’s east coast, leaving 307 people dead and 40,000 homeless.

  • The summer of 2007 was the wettest on record with 414mm of rainfall across England and Wales from May to July - more than in any period since records began in 1766. Across Yorkshire and the Midlands, thousands of people were rescued, whole towns cut off and families forced to flee their properties.

Source: FloodFlash Commercial Risk Report 2021

Source: FloodFlash Commercial Risk Report 2021

Greater London has the highest number of commercial properties in the 200 year flood zone (41,946) with over 4 times the properties at risk than the second place Manchester (10,024).

Flood Flash - Proportion of commercial properties in 200yr zone

The latest UK Climate Change Risk Assessment by the UK government presents compelling evidence (opens a new window) that climate change may lead to increases in heavy rainfall and significantly increased risks from fluvial and surface flooding by mid-century. Rising sea levels may further increase the risk of flooding and erosion along the UK’s coastline. 


  1. Research the flood risk for your business: a good rule of thumb for flood risk is that if many insurers don’t offer flood cover then you probably have a risk. A simple search on the site is a good place to start if you want more information. You may also want to consider a flood risk assessment from qualified surveyors to get a more specific view for your property.

  2. Register for flood warnings: sign up online for the government’s free service. Get alerts sent to your email or phone when your business is threatened by flooding.

  3. Create a flood plan: simple planning can give you clear actions when you receive a flood warning. Planning what stock or equipment you need to move, and who within your organisation is responsible for moving it, is a great way to limit the impact of a flood. The Environment Agency has many practical tips on how to create a flood plan.

  4. Establish what resilience measures you might benefit from: resilience measures include resistance and resilience. Resistance measures (also known as flood defences) prevent the water from entering your property e.g. flood gates or non-return valves. Resilience reduces the impact of the water once it has entered e.g. waterproofing or raising electrical points. Many companies that provide these services offer free surveys to establish what you might need. Make sure to avoid scammers though – they often prey on people who have suffered flooding in the past.

  5. Get insurance cover: it might seem obvious, but many businesses have been unable to get flood cover for 10+ years. Others have been priced out by big premiums or large excesses

Many businesses have been denied flood insurance cover or faced high premiums and large excesses. If they managed to attain cover and flooding occurs, it often takes several months until claims are settled as most policies are based on the damages caused by the flood which need to be assessed.

Lockton cooperates with FloodFlash (opens a new window), an insurtech firm that offers parametric flood insurance aimed at businesses and property owners. The policy pays a fixed sum as soon as flood water reaches a pre-agreed depth.

For more information on our services visit the Lockton Global Real Estate and Construction page on our website (opens a new window).