Research and analysis

Groundwater situation: Hampshire 11 April 2025

Updated 11 April 2025

Current situation

Groundwater levels across Hampshire are now slowly falling. In March, very little rainfall was recorded.

For most locations in Hampshire, it was the driest March since 1990, and in north-west Hampshire, it has been the driest March since 1961.

Dry weather has continued into April, with all rain gauges in Hampshire recording less than 1mm of rain in this month so far.

Groundwater flooding impacts are ongoing in isolated locations.

Impacts include:

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

These will reduce as we move towards the summer.

Graph showing changes in groundwater levels in Clanville Gate Borehole in North Hampshire from January 2023 to March 2025. The graph shows groundwater levels rising steadily from the beginning to October 2024 until mid-March 2025. Since then, levels have been slowly falling.

Graph showing changes in groundwater levels in Hursley Borehole in central Hampshire from January 2023 to March 2025. The graph shows an incline in groundwater level from the beginning of October 2024 until early March 2025. Since then, groundwater levels have been slowly falling.

Graph showing changes in groundwater levels in Whitedale Farm Borehole in East Hampshire from January 2023 to March 2025. The graph shows a steady incline in groundwater level from the beginning of October 2024 mid-March 2025. Since then, levels have been slowly falling.

Weather forecast

Over the next 5 days, very little rain is forecast. Groundwater levels in Hampshire are expected to continue slowly falling over the course of the next week.

Long range forecasting is difficult. From next week, the weather is expected to turn more unsettled, with heavy, thundery showers possible.

This heralds a wetter period through the middle of April with showers or longer spells of rain at times.

At the end of April and into May, a change to more settled conditions is more likely.

Forecast risk of flooding

In most years, groundwater levels typically reach a peak in March or early April and then start to fall as winter rain eases, temperatures rise, and plants start to grow and take up water.

With groundwater levels have peaked, we would expect that groundwater levels in Hampshire will generally continue to fall slowly and ongoing flooding impacts will decrease through the coming weeks and months.

Next update

With groundwater levels expected to continue to fall, and flood risk reducing, we are not planning to update this briefing note next month.

However, we will continue to monitor the levels and forecasts and will re-issue this briefing note at any time when new instances of groundwater flooding are thought possible.

We will likely re-issue this briefing note in autumn or winter 2025.

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