Research and analysis

East Anglia water situation: May 2026 summary

Updated 11 June 2026

Applies to England

• Publication for Northern Ireland
• Publication for Scotland
• Publication for Wales

East Anglia rainfall for May 2026 ranged from 28% to 60% of the long term average (LTA) for the month. The soil moisture deficit (SMD) for East Anglia at the end of May 2026 was 99mm with the majority of sites having SMDs between 26mm and 50mm greater than the LTA for the time of year. River flows were below normal, notably low or exceptionally low for the majority of sites. Groundwater levels have decreased across all sites but the majority of monitoring sites are still normal for this time of year. Public water supply reservoirs ended May 2026 with levels ranging from 87% to 92% of their full storage capacities. All reservoirs ended the month with levels below their normal operating curves for this time of year.

1. Rainfall

East Anglia received below normal rainfall in May 2026 with some areas experiencing notably low or exceptionally low rainfall. May 2026 rainfall totals across East Anglia ranged from 28% to 60% of the LTA for the month. The average rainfall across East Anglia for May 2026 was 19mm, which is 41% of the historic LTA and considered notably low for the time of year. The lowest rainfall totals were recorded in the Cam (13mm) and North Essex (12mm), with these catchments recording exceptionally low rainfall for the time of year. The cumulative rainfall totals over the past 3 months have been exceptionally low for all catchments. Over the past 6 and 12 months the cumulative rainfall totals have been normal in the majority of catchments with 2 catchment areas North Norfolk and North West Norfolk and Wissey recording below normal cumulative rainfall in the last 6 and 12 months.

2. Soil moisture deficit and recharge

The SMD for East Anglia has increased significantly during May 2026, rising from a notably high 66mm at the end of April to an exceptionally high 99mm at the end of May. The majority of catchments have SMDs between 26mm and 50mm greater than the LTA for the time of year. North Norfolk and the Lower Bedford Ouse were the exception with SMDs between 6mm and 25mm greater than the LTA for the time of year. SMD has improved slightly since April 2026 in 2 catchments, North Norfolk and the Lower Bedford Ouse moving from SMDs of 26mm to 50mm above the LTA to 6mm to 25mm above the LTA.

3. River flows

Following below average rainfall across East Anglia, the May 2026 month mean flows at the majority of monitoring sites have decreased compared to April 2026. Only 2 flow sites, Heacham and Burn, have normal flows with the rest of the monitoring sites being below normal, notably low or exceptionally low. Flows range between 29% of the LTA at Waveney to 84% of the LTA at Heacham.

4. Groundwater levels   

Groundwater levels have begun to fall in half the reporting sites, for which there is data available, for May 2026 compared to April 2026. Most sites are still normal for this time of year. Some sites are below normal with Hindolveston recording notably low groundwater levels for this time of year.

5. Reservoir stocks

All public water supply reservoirs for East Anglia have seen a decrease in storage for May 2026. At the end of the month, levels ranged from 87% to 92% of their full storage capacity. All reservoirs ended the month with levels below their respective normal operating curves for this time of year.

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.