East Anglia water situation: August 2025 summary
Updated 12 September 2025
Applies to England
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1. Summary
Rainfall for August 2025 was below average across all catchments in East Anglia, with rainfall totals ranging from 29% to 46% of the long term average for the month. The soil moisture deficit for East Anglia increased to 124mm at the end of August 2025, with South Essex and Central Area Fenland recording the highest soil moisture deficit values. River flows in the Ouse, Ivel and Rhee catchments maintained normal flow rates, with all other catchments classified as below normal or lower for the time of year. Groundwater levels at all sites continued to fall, with sites ranging from above normal to exceptionally low. Public water supply reservoirs in East Anglia ended August 2025 with levels ranging from 61% to 77% of full storage capacity.
2. Rainfall
August 2025 rainfall totals across East Anglia ranged from 29% to 46% of the long term average (LTA) for the month. The month began and ended with rainfall, with little to no rainfall received between 5 to 26 August. Average rainfall across East Anglia for August 2025 was 21mm, which is 35% of the historic LTA. The highest rainfall totals were recorded towards the west of the area, with the lowest rainfall recorded in East Suffolk. All catchments recorded notably low rainfall for August 2025, except the Little Ouse and Lark catchment, which recorded below normal rainfall. Cumulative rainfall totals over the past 6 months have been exceptionally low in all catchments, except for East Suffolk which has been notably low.
3. Soil moisture deficit and recharge
The soil moisture deficit (SMD) for East Anglia at the end of August 2025 was 124mm. South Essex and Central Area Fenland recorded the highest SMD values, ranging between 131mm to 160mm. Across East Anglia SMD was recorded as exceptionally high, with SMD ranging from 6mm to 50mm above the LTA for the time of year. Central Area Fenland and the Upper Bedford Ouse recorded the largest difference from the LTA.
4. River flows
River flows across East Anglia during August 2025 continued to recede, with most catchments responding to rainfall at the end of the month. River flows in August 2025 ranged from 3% to 90% of the LTA, with flows ranging from normal to exceptionally low for the time of year. The highest flows were recorded in the south west of the area, with the lowest flows concentrated towards the centre of the area. The Ely Ouse at Denver continued to record exceptionally low flows in August 2025, with the month mean flow recorded as 3% of the LTA.
5. Groundwater levels
Groundwater levels continued to fall in line with the expected seasonal pattern. Groundwater levels at the end of August 2025 ranged from above normal, at Therfield Rectory, North Hertfordshire Chalk to exceptionally low at The Spinney, Wensum Chalk. The majority of sites were categorised as normal or below normal for the time of year.
6. Reservoir stocks
Public water supply reservoirs within East Anglia finished August 2025 with levels ranging from 61% to 77% of full storage capacity. Alton, Ardleigh, Grafham and Hanningfield all ended August with levels below their respective normal operating curve. Abberton reservoir level was just above the respective normal operating curve for August.
7. Forward look
7.1 Probabilistic ensemble projections for river flows at key sites
River flow projections for the Bedford Ouse, Ivel, Kym and Ouse catchments all show a high probability of normal or higher flows for September 2025. Flow projections for the Ely Ouse show a high probability of below normal or lower flows for September 2025. River flow projections for December 2025 are varied with a high probability of normal to below normal flows.
7.2 Probabilistic ensemble projections for groundwater levels in key aquifers
Groundwater level projections for September 2025 are expected to be within the normal to below normal range, with the exception of Therfield Rectory which is expected to be above normal. Groundwater level projections for March 2026, show a high probability of below normal to notably low levels, again with the exception of Therfield Rectory which shows a high probability of normal or above groundwater levels.
Author: Hydrology Team, hydrology-ean-and-lna@environment-agency.gov.uk
All data are provisional and may be subject to revision. The views expressed in this document are not necessarily those of the Environment Agency. Its officers, servants or agents accept no liability for any loss or damage arising from the interpretation or use of the information, or reliance upon views contained in this report.