Research and analysis

Devon and Cornwall water situation: June 2025 summary

Updated 15 July 2025

Applies to England

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

1. Summary

Devon and Cornwall received 129% of the June long term average (LTA) rainfall, which was above normal for the time of year. Soil moisture deficit (SMD) decreased toward the middle of June, before increasing again and finishing the month at a similar deficit as the beginning of June. Monthly mean river flows were normal to notably high for the time of year across the area. Groundwater levels ended the month between normal to exceptionally high for the time of year. Total reservoir storage across Devon and Cornwall ended the month at 80%, with Wimbleball, Colliford and Roadford reservoirs at 72%, 73% and 87% respectively at the end of June.

2. Rainfall

Devon and Cornwall received 99mm of rain during June (129% of the June LTA), which is above normal for the time of year. The most significant periods of rain occurred during the first week of June and between 11 and 13 June. The remainder of the month was relatively dry, apart from localised pockets of rain.

In June, rainfall was normal or above normal in most hydrological areas, except the Avon, Dart and Erme hydrological area, which received notably high rainfall for the time of year. Rainfall totals were higher in the central hydrological areas, with the western hydrological areas of Cornwall and the eastern hydrological areas of Devon receiving less rain. Cumulative rainfall was mainly above normal in the last 3 months, except the North Cornwall hydrological area, which was notably high, and the hydrological areas in east Devon which were normal. Cumulative rainfall in the last 6 months also reflects mainly drier weather to the east (normal) and wetter weather to the west (above normal), apart from the Seaton, Looe and Fowey hydrological area where rainfall was also normal. In the last 12 months, cumulative rainfall was normal to above normal for the time of year across Devon and Cornwall.

3. Soil moisture deficit

SMD decreased during the first half of June, in response to the rainfall during this period, before increasing again and ending the month at a similar level to the beginning of the month. The average deficit for most of Devon and Cornwall was between 71mm and 100mm, apart from the Seaton, Looe and Fowey, Tamar and Avon, Dart and Erme hydrological areas where the average deficit was between 41mm and 70mm. The average deficit was highest in the Otter, Sid, Axe and Lim hydrological area recording a deficit of between 101mm and 130mm.

The difference between the SMD LTA and the SMD at the end of June reflected a similar pattern. The smallest difference of 6mm to 25mm was in the Seaton, Looe and Fowey, Tamar and Avon, Dart and Erme hydrological areas, with the largest difference of 51mm to 75mm in the Otter, Sid, Axe and Lim catchment. All other hydrological areas recorded a difference of 26mm to 50mm from the LTA for the time of year.

The SMD at the end of June was higher (drier) than the LTA for the time of year and higher (drier) than the SMD at the end of June 2024.

4. River flows

June monthly mean river flows were normal to notably high for the time of year at all sites across the area, with lower mean monthly flows in east Devon which reflects the spatial variation in rainfall throughout the month. 

Daily mean flows increased at all sites during the first part of June in response to heavy rainfall, before falling again in the second half of the month. On 30 June, all reporting sites in Devon and Cornwall recorded normal daily mean flows.

Due to data accuracy concerns, Thorverton on the River Exe, St Erth on the River Hayle, and Gunnislake on the River Tamar have been excluded from the June report.

5. Groundwater levels   

On 30 June, groundwater levels were classed as normal at:

• Bussels No7A (monitoring the Dawlish Sandstone)
• Coleford Production (monitoring the Permian Breccias and Sandstones)
• Winnards Perch (monitoring the Staddon Formation)
• Woodbury Common No2 (monitoring the Budleigh Salterton Pebble Beds)
• Woodleys No1 (monitoring the Otterton Sandstone Formation)

They were classed as above normal at Branscombe Lane (monitoring the Dawlish Sandstone) and exceptionally high at Whitlands (monitoring the Upper Greensand).

Groundwater levels at all sites continue to be in recession, which is normal for the time of year.

6. Reservoir stocks

Total reservoir storage was 80% at the end of June, which is an overall decrease in storage of 6% since the end of May. This is higher than storage at the same time in 2022 (the most recent drought year), which was 68%. At the end of June, storage at Wimbleball, Colliford and Roadford was 72%, 73% and 87% respectively, compared to 65%, 58%, and 76% at the same time in 2022.

Author: Devon and Cornwall Hydrology, hydrology.dandc@environment-agency.gov.uk

All data are provisional and maybe subject to revision. The views expressed in this document are not necessarily the views of the Environment Agency. Its officers, servants, or agents accept no liability for loss or damage arising from the interpretation or use of the information, or reliance upon views contained in this report.