Kent and South London water situation: June 2025 summary
Updated 15 July 2025
Applies to England
© Crown copyright 2025
This publication is licensed under the terms of the Open Government Licence v3.0 except where otherwise stated. To view this licence, visit nationalarchives.gov.uk/doc/open-government-licence/version/3 or write to the Information Policy Team, The National Archives, Kew, London TW9 4DU, or email: psi@nationalarchives.gov.uk.
Where we have identified any third party copyright information you will need to obtain permission from the copyright holders concerned.
This publication is available at https://www.gov.uk/government/publications/water-situation-local-area-reports/kent-and-south-london-water-situation-june-2025-summary
1. Summary
The whole Kent and South London (KSL) area received 66% of the long term average (LTA) rainfall during June. Rainfall received was normal across most catchments. Soil moisture deficits (SMDs) continued to increase and ended the month above the LTA. Monthly mean river flows (MMFs) ranged from normal to exceptionally low in June in KSL. Across the whole area, on average, effective rainfall received this month was at 63% of the LTA. Groundwater levels in the Chalk and Greensand aquifers continued to decline at all key sites throughout June and ended the month in the normal category. Levels at the end of the month at the five water company reservoirs also continued to decline and ranged between normal and exceptionally low.
2. Rainfall
The whole KSL area received 66% of the LTA rainfall during June. Rainfall received was normal across most catchments. The percentage of LTA rainfall received ranged from 55% in the South London area to 85% in the Thanet Chalk and Dover Chalk rainfall areas. In the previous 3 months, spanning from April to June, 6 catchments recorded exceptionally low rainfall, and the remaining 8 catchments recorded notably low rainfall. In the previous 6 months, from January to June, rainfall was below normal across catchments in the southern part of the patch. In the northern part of the patch, rainfall was mostly notably low. In the last 12 months, rainfall received was normal in most catchments in KSL area. Notably low and below normal rainfall were recorded in four catchments in the northeast. The highest daily rainfall total of 67.7mm for June was recorded at Dover WW RG in the Dover Chalk catchment on 13 June. The next highest daily rainfall totals were on 6,7, 5 and 4 June respectively and ranged from 31.2mm to 11mm. One day with less than 0.2mm of rainfall was recorded this month.
3. Soil moisture deficit and recharge
At the end of June, SMDs increased across all catchments. This is due to the low effective rainfall during this period, which averaged 63% of the LTA across the entire Area. The majority of SMDs were in the 71mm to 100 mm range at the end of May. By the end of June in most areas SMDs had shifted into the 101mm to 130 mm category, with some reaching as high as 158 mm. At the end of June, SMDs were significantly above the LTA, with the difference widening across all catchments since the end of May.
4. River flows
MMFs ranged from normal to exceptionally low in June in KSL. Four key flow sites saw normal MMFs, 5 saw below normal MMFs, and 2 registered exceptionally low MMFs in June. Exceptionally low flows were recorded in the River Ravensbourne at Catford in the northwest and in the River Stour at South Willesborough in the east of the patch.
5. Groundwater levels
Groundwater levels in the Chalk declined at a relatively steep rate. However, they remained within normal ranges for this time of the year by the end of June. Groundwater levels at the Lower Greensand aquifer at Riverhead have also continued to decrease and remained within the normal range. The fall in groundwater levels is consistent with the effective rainfall of 63% of the LTA and SMDs registered by the end of June.
6. Reservoir stocks
At the end of June, reservoir levels were:
- notably low at Darwell at 55%
- below normal at Bough Beech at 75% and at Bewl at 74%
- normal at Powdermill at 80%
- above normal at Weir Wood at 94%
7. Environmental impact
Hands off flow (HoF) constraints were applied to certain licensed abstractions linked to Udiam gauging station in the Eastern Rother catchment during June. HoF constraints continue to apply to certain licensed abstractions within the Stour and Medway catchments.
Author: Groundwater and Hydrology Team, ksl.gwh@environment-agency.gov.uk
Contact Details: 03708506506
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.