Lincolnshire and Northamptonshire water situation: May 2026 summary
Updated 11 June 2026
Applies to England
© Crown copyright 2026
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May 2026 was another dry month across Lincolnshire and Northamptonshire with 31mm of rainfall recorded, just 62% of the long term average (LTA). With another dry month following on from April, in which just 6mm was recorded, river flows and groundwater levels continued to drop. Six of the eleven key river flow sites recorded below normal flows for the month while May also saw groundwater levels dropping at all key indicator sites. The soil moisture deficit increased by 41.7mm compared to the end of April. Reservoir stocks are now close to, or below, their normal operating curve as demand increases.
1. Rainfall
Across Lincolnshire and Northamptonshire (LNA), May 2026 recorded an average rainfall of 31mm, equivalent to 62% of the LTA. Through the 6 hydrological areas, totals ranged from 23mm in the Lower Welland and Nene to 36mm in the Louth Grimsby and Ancholme, 48% to 78% of their respective LTA. Four of the 6 hydrological areas experienced below normal rainfall for the time of year, while two were classified as normal.
Continued dry weather over the past 3 months has meant LNA has experienced the eighth driest March to May on record, with just 37% of the LTA rainfall over that period. In addition, the Lower Welland and Nene and the South Forty-Foot and Hobhole recorded their fourth driest March to May, recording just 47mm and 49mm of rain respectively. Five of the 6 hydrological areas recorded exceptionally low rainfall, while the Louth Grimsby and Ancholme received 86mm, 65% of the LTA, and notably low for the time of year.
Despite the previous 3 months being exceptionally dry, the last 6 and 12 month periods have not been as severe. From December to May, LNA has received 320mm of rain, 113% of the LTA and normal for the time of year. Four of the 6 hydrological areas recorded normal rainfall over that period with the lowest percentage of the LTA being 106%, while the Witham to Chapel Hill and the Upper Welland and Nene both recorded above normal rainfall totals. Similarly, over the past twelve months LNA has received 104% of the LTA rainfall and 4 of the 6 hydrological areas have also recorded normal levels, between 98% and 102% of the LTA. The Louth Grimsby and Ancholme and the Witham to Chapel Hill areas recorded above normal rainfall over the twelve-month period, 114% and 110% of the LTA respectively.
2. Soil moisture deficit and recharge
Over the course of the last month, the soil moisture deficit (SMD) across LNA has increased by 41.7mm, from 66.5mm during the last week of April, to 108.2mm by the end of May. Four of the 6 hydrological areas had an SMD between 101mm and 130mm by the end of the month, while the Louth Grimsby and Ancholme and the Upper Welland and Nene had an SMD between 71mm and 100mm. All 6 hydrological areas have an SMD 26mm to 50mm greater than the LTA, highlighting the impact the lack of rainfall has had on the soil moisture across the area.
3. River flows
Flows at our key indicator sites continued to drop during May 2026, with 6 of the 11 sites with data averaging below normal flows for the month, in comparison to April in which 10 of the 11 sites recorded normal flows for the time of year. Flows ranged from 30% of the LTA, on the Welland at Barrowden/Tixover, to 100% of the LTA, on the Lud at Louth. Gauging issues at Rase Bishopbridge on the River Rase has meant there is no available data at the site for May 2026.
4. Groundwater levels
Groundwater levels at most of the key indicator sites remain healthy, although they are declining in response to the lack of rainfall over the past couple of months. By the end of May 2026, 8 of the 10 sites had groundwater levels normal or above for the time of year, however 6 of the 10 sites had dropped down a classification over the course of the month. Two sites are now below normal, or lower, for the time of year – Dunholme Road and Grange de Lings, situated on limestone to the north of the area.
5. Reservoir stocks
Reservoir levels across LNA began to decrease through May 2026 as the dry, warm weather continued. All sites saw levels drop to below, or very close to, their normal operating curve with stocks ranging from 87.9% full at Pitsford to 97.5% full at Covenham. The average level across the 5 reservoirs by the end of May 2026 was 91.92% full.
Author: Pan Hydrology Team, Hydrology-EAN-and-LNA@environment-agency.gov.uk
Contact Details: 03708 506 506
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