Research and analysis

Yorkshire water situation: September 2026 summary

Updated 14 October 2026

Applies to England

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

1. Summary

Rainfall in Yorkshire was below the long term average (LTA) for the time of year in all catchments this month. Soils remained dry or very dry throughout the month. River flows were below the September LTA in all catchments and by the end of the month were below normal for the time of year. Groundwater levels decreased in most principal aquifers. Reservoir stocks continued to decline and were around 20% below the LTA for the time of year at the end of the month. A substantial number of hand off flow (HoF) restrictions on abstractions were in place by the end of the month.

2. Rainfall

Catchment average rainfall in September was below the LTA for the time of year in all Yorkshire catchments. It was also the fourth consecutive month of below LTA rain in Yorkshire. Pennine catchments had either normal or below normal rainfall with between 46% and 82% of LTA rainfall. However, catchments in the east only had between 26% and 39% of the LTA. In particular, the Hull rainfall total for the month was exceptionally low for the time of year.

During September there was episodic rainfall across Pennine catchments between days 1 and 19. The larger daily totals, in excess of 10mm, occurred over the northern and central Pennine catchments of the Ure, Nidd, Wharfe, Aire and Calder on days 3, 7 and 18. In the Swale catchment there were fewer days with rain and the daily totals were lower. For all Pennine catchments there followed a dry period between days 20 and 27 before a return to occasional, low daily rainfall totals at the end of the month.

In southern and eastern Yorkshire rainfall was sporadic throughout the month and, as in the Pennine catchments, the only notable daily totals occurred on days 3, 7, and 18. These catchments were predominantly dry from day 19 to the end of the month.

For Yorkshire as a whole it was the fifth lowest April to September rainfall accumulation since 1871. In the south and west, the 6-month April to September cumulative rainfall totals were notably low and they were exceptionally low in the north and east. The April to September total in the Esk catchment was the second lowest on record, with only the 1991 total being lower.

3. Soil moisture deficit and recharge

Soils across Yorkshire began the month dry and remained so until day 15. During this period the rainfall in Pennine catchments reduced soil moisture deficits (SMDs) slightly but deficits in southern and eastern catchments continued to increase. The drier weather from mid-month caused all SMDs across Yorkshire to increase. By the end of the month, soils in the south and east of Yorkshire were very dry and those of the Pennines remained dry with deficits close to that at the start of the month. By the end of the month SMDs were lower than the September LTA.

4. River flows

Monthly mean flows were below their September LTAs in all catchments across Yorkshire. The monthly mean flows also generally reflect the distribution of rainfall across catchments in September. Although the catchments of the Ure, Wharfe and Aire had normal monthly mean flows for the time of year, it is possible that the below normal flows in the Nidd and Calder were influenced by reservoir storage in these catchments. The lack of September rainfall in southern and eastern catchments was reflected by below normal and notably low monthly mean flows. In the Esk catchment, at Briggswath, the monthly mean flow was exceptionally low for the time of year and the lowest September mean flow on record.

Pennine catchments had notably high or above normal daily mean flows on days 4 and 19, in response to the larger rainfall totals of days 3 and 18. By the end of the month Pennine catchment flows had declined to below normal or notably low for September. Flows in the Swale followed a similar pattern but increased to normal flows in response to rainfall before returning to notably low between each event and then declining to exceptionally low by the end of the month.

In the Derwent, Esk and Rye catchments of the North Yorkshire Moors, response to rainfall on days 3, 7 and 18 was less pronounced. Overall, there was a steady decline from below normal flows for the time of year at the beginning of September to exceptionally low flows by the end of the month. In the Hull catchment there was a similar pattern of gradual decline but from below normal to notably low flows for the time of the year.

5. Groundwater levels   

5.1 Magnesian Limestone

The groundwater level within the Magnesian Limestone decreased at Brick House Farm and was normal for the time of year.

5.2 Millstone Grit

There was no data available for September at the Hill Top Farm monitoring well. At the end of August, the groundwater level within the Millstone Grit at Hill Top Farm was notably low for the time of year.

5.3 Sherwood Sandstone

The groundwater level within the Sherwood Sandstone remained stable at Great Ouseburn and was normal for the time of year. The groundwater level increased at Riccall Approach Farm and was below normal for the time of year.

5.4 Corallian Limestone

The groundwater level within the Corallian Limestone decreased at Sproxton and was normal for the time of year.

5.5 Chalk

The groundwater level within the Chalk decreased at Wetwang and was notably low for the time of year. The groundwater level decreased at Dalton Estate Well and was below normal for the time of year.

6. Reservoir stocks

Reservoir stocks continued to decline over the course of September at an average rate of around 0.8% per week. At the end of the month, stocks were at 45.8%, the lowest level recorded so far in 2026, and were 21.4% less than the LTA.

7. Environmental impact 

At the end of September, there were 113 abstraction licences with a HoF condition in force, and another 45 abstraction licence holders had been given advance warning of possible restrictions.

Author: Yorkshire Hydrology Team, hydrology.northeast@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.