Research and analysis

Yorkshire water situation: September 2025 summary

Updated 14 October 2025

Applies to England

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

1. Summary

Rainfall in September was above average across all of Yorkshire and was concentrated between days 10 and 20. Flows began the month low but peaked in response to the rainfall before returning to normal in most catchments. Over the month, soil moisture deficits were substantially reduced on the Pennines but this effect was much less significant in the east and south. Reservoir stocks increased significantly but remained well below the long term average (LTA) for the time of year.

2. Rainfall

Rainfall this month was above normal for the first time since February. The monthly rainfall totals were high and ranged from 147% of the LTA in the Derwent catchment to 201% in the Nidd catchment.

The Ure, Nidd, Wharfe and Aire catchments had scattered rainfall for the first few days of the month and then returned to settled and dry conditions until day 10. There followed prolonged rainfall, which became particularly intense on day 20, when most gauges recorded over 40mm. The next 6 days were mostly dry and then there were small amounts of rain on days 27 and 30. In each of these catchments the total September rainfall was exceptionally high for the time of year, especially in the Wharfe which had the fifth wettest September since 1871.

The remaining Pennine catchments of the Swale, Ouse, Don and Rother had notably high amounts of rainfall. The rain followed a similar pattern to other Pennine catchments but with lower monthly totals and less rain between 10 and 20 September.

The Esk, Rye, Derwent and Hull all had notably high rainfall. The Esk catchment received 92% of the month’s LTA on 20 September at both Easby and Westerdale.

3. Soil moisture deficit and recharge

Soils began the month very dry across most of Yorkshire. The substantial rainfall of the third week meant that during the month soil moisture deficits reduced across the whole county. By the end of the month soils in the northern and western Pennines were wet and almost completely saturated. In the Vale of York and over the North Yorkshire Moors soil moisture deficits had returned to normal for the time of year. In the southern Pennines and in the east of Yorkshire there was a small reduction in soil moisture deficits but nonetheless they remained dry for the time of year.

4. River flows

In September flows increased across the majority of catchments. The only exception was the Chalk fed catchment of the West Beck in the east of Yorkshire .

Monthly mean flows in the northern Pennines were high and ranged between 130% and 214% of the LTA. Flow in the upper Wharfe was exceptionally high, responding to the periods of intense rainfall in the catchment. Elsewhere, monthly mean flows were lower and ranged from 49% to 114% of the LTA.

Daily average flows were exceptionally low in many catchments at the beginning of September. Flows in the Pennine catchments remained low until 11 September and then responded to rainfall events on 11, 15 and 20 September. Flows in the Swale, Ure, Nidd, Aire and Ouse all reached exceptionally high levels between 15 to 17 September before receding. They then peaked again on 20 to 22 September, again to exceptionally high flows. Flows in the Nidd then remained above normal for the rest of the month, but elsewhere they quickly returned to normal flows.

In the Rye, Esk and Derwent catchments, flows remained notably low and exceptionally low for much of the first two weeks of the month. There was a small response to rainfall around 16 September. The most significant increases in flow took place on 20 September, during which the Esk and Rye flow was exceptionally high, and 21 September when flows in the Derwent became notably high.

Flows in the Don and Rother reacted slightly to rain on 3 and 4 September. In a similar manner to other catchments they also reached exceptionally high flows on 20 and 21 September before receding to normal flows.

The West Beck was notably low for much of the month, a result of the continued low groundwater levels in the chalk. Flows briefly reached normal levels on 4 September.

5. Groundwater levels   

5.1 Magnesian Limestone

The groundwater level within the Magnesian Limestone increased at Brick House Farm and became notably high for the time of year.

5.2 Millstone Grit

The groundwater level within the Millstone Grit decreased at Hill Top Farm and was exceptionally low for the time of year. This observation borehole is used for water abstraction by means of a pump which may affect the groundwater level recorded here.

5.3 Sherwood Sandstone

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

5.4 Corallian Limestone

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

5.5 Chalk

The groundwater level decreased at Wetwang and was notably low for the time of year. The groundwater level also decreased at Dalton Estate Well and was notably low for the time of year.

6. Reservoir stocks

Reservoir stocks increased significantly this month. In the third week, they increased by 15.6% which is one of the largest weekly increases on record. At the end of September, stocks were at 46.5%, still 21.4% less than the LTA for the time of year.

7. Environmental impact 

In late September, there were 42 abstraction licences with a hands off flow condition in force, and another 106 abstraction licence holders had been given advance warning that flows were low.

Author: Environment Agency, hydrology.northeast@environment-agency.gov.uk

Contact Details: 020 847 48174

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.