Research and analysis

Devon and Cornwall water situation: September 2026 summary

Updated 14 October 2026

Applies to England

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

1. Summary

Devon and Cornwall received 77mm of rain during September. This is 87% of the September long term average (LTA), which is normal for the time of year. Devon and Cornwall experienced the eighth driest 7 months (March to September) in a 155-year record. Soil moisture deficit (SMD) decreased overall but remained higher (drier) than the LTA throughout September. September monthly mean flows ranged from exceptionally low to normal across the area. Groundwater levels ended the month between exceptionally high and notably low for the time of year. Total reservoir storage across Devon and Cornwall on 27 September was 37%, with Wimbleball, Colliford and Roadford at 21%, 39% and 43% respectively. 

2. Rainfall 

Devon and Cornwall received 77mm of rain during September (87% of the September LTA), which is normal for the time of year. All hydrological areas recorded normal rainfall totals for the time of year, other than the Exe and Otter, Sid, Axe and Lim which recorded below normal rainfall totals (66% and 58% of the September LTA respectively). The highest rainfall totals for Devon and Cornwall were on 7 and 29 September. 

Cumulative rainfall for the last 3 months was notably low for most of the area. The Exe, Teign and Torbay and Otter, Sid, Axe and Lim hydrological areas recorded exceptionally low 3-month cumulative rainfall totals. North Cornwall was the only area to record a below normal 3-month cumulative rainfall total. Over the past 6 months, cumulative rainfall was below normal for the majority of the area. The Avon, Dart and Erme and Taw and North Devon Streams areas recorded notably low 6-month cumulative rainfall totals. The Exe, Teign and Torbay and Otter, Sid, Axe and Lim areas recorded exceptionally low 6-month cumulative rainfall totals. Over the past 12 months, cumulative rainfall was notably high for most of the area. Torridge and Hartland Streams and Teign and Torbay areas recorded above normal 12-month cumulative rainfall totals, with Exe and Taw and North Devon areas recording normal 12-month cumulative rainfall totals.  

Devon and Cornwall experienced the eighth driest 7 months (March to September) in a 155-year record. It was the second driest 7 months on record in the Exe and Otter, Sid, Axe and Lim area, and the third driest 7 months on record in the Teign and Torbay area. 

3. Soil moisture deficit  

SMD in Devon and Cornwall decreased overall (soils became wetter) during September. At the end of September, SMD was considerably higher (drier) than the LTA for this time of year. 

At the end of September, SMD ranged from 101mm to 130mm in the Exe hydrological area and 131mm to 160mm in the Otter, Sid, Axe and Lime hydrological area. All other hydrological areas had an SMD of 71mm to 100mm. The SMD in the majority of Devon and Cornwall was 26mm to 50mm higher than the LTA for the time of year. SMD was 51mm to 75mm higher than the LTA for the time of year in the Teign and Torbay, Exe and Otter, Sid, Axe and Lim hydrological areas. SMD was 6mm to 25mm higher than the LTA for the time of year in the West Cornwall and Seaton, Looe and Fowey hydrological areas. 

4. River flows 

September monthly mean river flows were classed as exceptionally low to normal across Devon and Cornwall. Chudleigh Bridge on the river Teign, St Erth on the river Hayle and Umberleigh on the River Taw recorded exceptionally low September monthly mean river flows. 

Daily mean flows were higher at the end of September than at the end of August due to the rainfall received in September, with peaks in flow at the beginning and end of the month in response to the highest rainfall totals on the 7 and 29 September. Daily mean flows on 30 September were between normal and below normal, with the exception of the East Dart River at Bellever recording above normal flow. Flows at Gwills on the river Gannel, Bodmin Dunmere on the river Camel and Chudleigh Bridge on the river Teign increased from exceptionally low on 28 September to normal on 30 September. The East Dart River at Bellever increased from notably low on 28 September to above normal on 30 September as a result of considerable rainfall on 29 September.  

5. Groundwater levels   

On 29 September, groundwater levels were classed as follows: 

• notably low at Winnards Perch (monitoring the Staddon Formation) 

• below normal at Coleford Production (monitoring the Permian Breccias and Sandstones) 

• normal at Bussels No7A (monitoring the Dawlish sandstone), Woodleys No1 (monitoring the Otterton Sandstone Formation) and Woodbury Common No2 (monitoring the Budleigh Salterton Pebble Beds) 

• above normal at Branscombe Lane (monitoring the Dawlish Sandstone) 

• exceptionally high at Whitlands (monitoring the Upper Greensand) 

Groundwater levels are lower at the ‘secondary aquifer’ sites (Winnards Perch and Coleford Production) than at the other sites, which are ‘principal aquifer’. This is because secondary aquifers have a lower storage and respond more rapidly to a lack of recharge from rainfall.  

6. Reservoir stocks  

Total reservoir storage was 37% on 27 September, which is an overall decrease of 11% since the end of August. This is higher than storage at the end of September 2022 (the most recent drought year), which was 33%. On 27 September, storage at Wimbleball, Colliford and Roadford was 21%, 39% and 43% respectively, compared to 24%, 21% and 39% 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.