Current situation

Over autumn and winter 2024 to 2025, Sussex has recorded slightly above average rainfall. The end of September 2024 and the end of November 2024 were particularly wet. January 2025 began and ended with a lot of rain, but very little rainfall was recorded through the middle of January. Only a small amount of rain has been recorded in February, so far.

Groundwater levels in Sussex are roughly average for the time of year. In some locations, groundwater is a little higher than average for the time of year. However, no groundwater flood impacts are thought to be currently occurring, and groundwater is now slowly falling.

Graph showing changes in groundwater levels in Compton Borehole in West Sussex from December 2022 to February 2025. The graph shows that groundwater levels are currently about average.

Graph showing changes in groundwater levels in Ladies Mile Borehole near Brighton from December 2022 to February 2025. The graph shows that groundwater levels are currently about average.

Weather forecast

No rainfall is forecast for the 5 days from 14 February 2025.

Long term weather forecasting is extremely difficult. There remains uncertainty and predictions might change, but currently, unsettled conditions with wind and rain at times are expected to affect the UK through the last week of February, and the beginning of March 2025.

Forecast risk of flooding

We predict that groundwater will initially continue to fall in all indicator boreholes across Sussex, through February, and probably through March too. Groundwater will not fall far.

If the end of February is very wet, a small rise in groundwater levels could be possible, through the last few days of February and start of March. However, even if groundwater rises, it probably will not rise significantly, and it is highly likely that flood impacts will not occur in Sussex this winter, or spring.

It is very difficult to accurately predict the weather weeks or months ahead, and the forecast might change. The exact groundwater response will depend on the amount, intensity and distribution of any rainfall that occurs. If we experience an above average, or an exceptional amount of rainfall over the weeks ahead, then there is a small possibility for minor groundwater flood impacts to occur in communities across Sussex, perhaps from early March 2025. With impacts including small amounts of water in fields, on roads, and in a small number of basements. Potentially in groundwater communities in Sussex: Lavant Valley, Ems Valley, Patcham, Lewes, and Newhaven.

Next update

We will update this groundwater situation document by 7 March 2025, or sooner if the risk of groundwater flooding significantly increases. When in force, groundwater Flood Alerts are updated with information more frequently.

What we are doing

We continue to monitor groundwater levels and their response to rainfall.

Throughout autumn and winter, we will update this groundwater situation and our groundwater Briefing Notes.

We will issue and update flood alerts when there is risk of flooding affecting property.

We liaise with the local authority and other responding partners to ensure they are aware of the situation.

Our operational staff will remove blockages from main rivers, to ensure they flow freely.

Actions and advice

Think and prepare now for what you’ll do if flooding occurs where you live, don’t wait until flooding happens.

Call Floodline on 0345 988 118 or visit check for flooding to find out if you can register to receive free flood alerts for flooding from groundwater.

Look for data in your area:

• groundwater data
• river, sea, groundwater and rainfall levels

There is practical advice on what to do before, during and after groundwater flooding, and further guidance about groundwater flooding, how it might affect you and what to do.

Prepare a personal flood plan or community flood plan to help you and your community decide what practical actions to take before and during a flood, which will help reduce the damage flooding could cause.

Check pumps and any other flood protection equipment you have. Ensure valuables are moved from basements and other low parts of properties.

Where safe to do so, communities may wish to check and ensure there are no blockages in local watercourses and ditches.

Further information

You can view:

• daily groundwater levels compared to average and maximum, with indicative impact thresholds
• sub daily groundwater levels on Gaugemap
• the latest flood alert information
• water situation reports

More detailed groundwater briefing notes are emailed as part of the flood alert service. See contacts section below to register your email address.

Contacts

For more information on the flood alert service and to find out what messages you are registered to receive, call Floodline on 0345 988 118.

Alternatively, you can contact the following for additional information:

• Environment Agency Customers and Engagement: ssdenquiries@environment-agency.gov.uk
• Environment Agency Incident Reporting Hotline: 0800 807060
• Environment Agency National Customer Contact Centre: 03708 506 506