Devon and Cornwall water situation: December 2025 summary
Updated 14 January 2026
Applies to England
© Crown copyright 2026
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Devon and Cornwall received 142% of the December long term average (LTA) rainfall, which was notably high for the time of year. Soil moisture deficit (SMD) increased overall during December. Monthly mean river flows were above normal to exceptionally high for the time of year across the area. Groundwater levels ended the month between normal and exceptionally high for the time of year. Total reservoir storage across Devon and Cornwall on 28 December was 80%, with Wimbleball, Colliford and Roadford at 73%, 65% and 86% respectively.
1. Rainfall
Devon and Cornwall received 216mm of rain during December (142% of the December LTA), which is notably high for the time of year. The first 3 weeks of December were unsettled, with 99% of the month’s rain falling by 21 December. The final week of the month was notably dry, with the highest periods of rainfall falling during the first 3 weeks of the month, before a notably dry final week.
All hydrological areas reported notably high rainfall for the time of year, except Taw and North Devon Streams which was normal for the time of year, and the Exe and Torridge and Hartland Streams which were above normal for the time of year.
Cumulative rainfall for the last 3 months was notably high across the area except for the:
- Tamar, which experienced exceptionally high rainfall
- Torridge and Hartland Streams, Taw and North Devon Streams and Exe hydrological areas, which experienced above normal rainfall
Over the last 6 to 12 months, rainfall was normal to notably high across all hydrological areas, generally trending drier towards eastern parts of Devon.
2. Soil moisture deficit
SMD decreased during the first half of December, before increasing towards the end of the month, reflecting the dry end to a generally wet month. SMD remained close to the LTA, ranging from 5mm lower (wetter) to 5mm higher (drier) than the LTA deficit for December across the area. The average SMD deficit at the end of December was below 10mm across the whole area.
3. River flows
December monthly mean river flows ranged from above normal to exceptionally high across Devon, with all sites in Cornwall experiencing exceptionally high flows except the Tamar (Gunnislake) which was notably high.
All sites showed exceptionally high daily flows in the first 3 weeks of the month, before receding in the final week. Daily mean flows on 31 December ranged from normal to below normal across Devon and Cornwall, except for the Torridge (Torrington) which ended the month notably low.
4. Groundwater levels
On 31 December, groundwater levels were classed as:
- normal at Woodbury Common No2 (monitoring the Budleigh Salterton Pebble Beds), Woodleys No1 (monitoring the Otterton Sandstone Formation), Coleford Production (monitoring the Permian Breccias and Sandstones) and Winnards Perch (monitoring the Staddon Formation)
- above normal at Bussels No7A (monitoring the Dawlish sandstone) and Branscombe Lane (monitoring the Dawlish Sandstone)
- exceptionally high at Whitlands (monitoring the Upper Greensand)
Groundwater levels at all sites except Whitlands have begun their seasonal recovery after their summer and autumn recession. Winnards Perch’s hydrograph is very ‘noisy’, as levels at this site respond quickly to rainfall variations due to the low storage of the secondary aquifer which it monitors.
5. Reservoir stocks
Total reservoir storage was 80% on 28 December, which is an overall increase of 15% since 30 November. This is higher than storage at the same time in 2022 (the most recent drought year), which was 57%. On 28 December, storage at Wimbleball, Colliford and Roadford was 73%, 65% and 86% respectively, compared to 63%, 33% and 49% 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.