Current situation

Groundwater levels in West, North and Central Hampshire are very high. In East Hampshire, groundwater levels are around average for this time of year.

January 2025 was wetter than normal, with all rain gauges in Hampshire recording between 120 and 190mm of rainfall.

This is between 105 and 205% of the long-term average for this month.

February has started relatively dry, with all rain gauges recording between 5 and 20mm of rainfall.

During February, groundwater levels have been rising in response to the January rain, but the rate of rise has slowed, and in some locations, levels have stabilised and started to slowly fall.

Groundwater flooding impacts are ongoing in several susceptible communities. Impacts include:

• winterbourne streams flowing
• flooding to land, roads and cellars
• the inundation of sewerage systems and septic tanks

Flood water on the road may cause icy conditions during spells of cold weather.

Weather forecast

Over the next 5 days, only small amounts of rain are forecast to affect Hampshire. In most susceptible locations, groundwater levels are expected to peak within the next week and then will begin to slowly fall.

Long range forecasting is difficult. During the week beginning 17/02/2025, it is likely that progressive frontal rain bands could begin to push across England. The theme of unsettled weather is likely continue during the end of February and into March, bringing bands of rain interspersed with some drier interludes.

Forecast risk of flooding

If heavy rain affects Hampshire during this period, then groundwater levels will begin to rise once more.

Groundwater flooding impacts, such as cellar flooding, road flooding, and inundation of septic tanks and sewerage networks, could occur in more susceptible locations by late-February or early March.

The additional communities most at risk of groundwater flooding impacts within the coming weeks are the Bourne Valley, villages close to Winchester, Kings Somborne and Little Somborne, Cheriton, Twyford and Hensting.

If heavy rain occurs over the coming months, then all susceptible locations in Hampshire could experience flooding impacts during this winter.

If we record an average amount of rainfall in the coming weeks, then levels will slowly fall as we move into spring, with most locations in Hampshire avoiding groundwater flooding impacts during this winter.

Next update

We will update this groundwater situation document by 14 March 2025. When in force, groundwater Flood Alerts are updated with information more frequently.

What the Environment Agency are doing

We will:

• continue to monitor groundwater levels and their response to rainfall. 
• update this groundwater situation document and our groundwater briefing notes throughout autumn and winter
• issue and update flood alerts when there is risk of flooding affecting property
• liaise with the local authority and other responding partners to make sure they are aware of the situation
• remove blockages from main rivers, to make sure they flow freely

Actions and advice

Think and prepare now for what you will do if flooding occurs where you live, do not 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. Move valuables 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 
• groundwater situation information for North Hampshire (Alton, Basingstoke, Crondall, Farringdon, Sherborne St John) 
• water situation reports  

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

Contact

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, for more information, you can contact: 

• 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