Kent and South London water situation: July 2025 summary
Updated 12 August 2025
Applies to England
© Crown copyright 2025
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1. Summary
The entire Kent and South London (KSL) area received 174% of the long-term average (LTA) rainfall during July. Rainfall received across individual catchments ranged from normal to notably high. Soil moisture deficits (SMDs) throughout most catchments continued to increase during July and ended the month above the LTA. Monthly mean river flows (MMFs) ranged from below normal to above normal in July in KSL. Groundwater levels in the Chalk remained mostly normal across KSL area at the end of July. Groundwater levels in the Greensand aquifer at Riverhead increased slightly and are now above normal levels. Levels at all the 5 water company reservoirs declined throughout July, ending the month in categories ranging from notably low to above normal.
2. Rainfall
The entire KSL area received 174% of the LTA rainfall during July. Rainfall received across individual catchments ranged from normal to notably high. The percentage of LTA rainfall received ranged from 106% in the Lower Mole rainfall area to 213% in the Stour rainfall area. In the previous three months, spanning from May to July, 5 catchments in the northwest recorded below normal rainfall. The remaining nine catchments recorded normal rainfall. In the previous 6 months, from February to July, rainfall ranged from exceptionally low to normal in KSL. Catchments in the west of the patch received rainfall furthest below their LTA for this time period. In the last 12 months, rainfall received was normal in most catchments across KSL area. Below normal rainfall was recorded in three catchments in the north and northeast. The highest daily rainfall total of 56.3mm for July was recorded at Eastry STW RG in the Stour catchment on 6 July. The next highest daily rainfall totals were on 20, 23 18 and 21 July respectively and ranged from 42.8mm to 30.3mm. No dry days with less than 0.2mm of rainfall were recorded this month.
3. Soil moisture deficit and recharge
SMDs increased across most catchments from the end of June to the end of July, despite above average effective rainfall. At the end of July, SMDs across catchments ranged from 117mm to 165mm. On the last day of July, SMDs throughout all catchments in the west and north of the patch sat within the 131 to 160mm range. Although the KSL area averaged 159% of its LTA effective rainfall in July, SMDs still increased in most catchments due to uneven rainfall distribution. Compared to the end of June, most catchments saw SMDs move closer to their LTAs by the end of July, despite overall increases in deficit values.
4. River flows
MMFs ranged from normal to above normal in July in KSL. Above normal flows were observed at the River Teise at Stonebridge – the only key site with MMFs in this category. Below normal flows were registered at the River Ravensbourne at Catford in the northwest, and at the River Rother at Udiam in the south of the patch. All other keys sites recorded normal MMFs.
5. Groundwater levels
Groundwater levels in the Chalk remained mostly normal across KSL area at the end of July. Only Chipstead in the west of the patch recorded below normal levels for this time of year on the last day of the month. Levels in the Isle of Thanet at Fleete Reservoir overcame the seasonal trend and started rising in late July. Groundwater levels in the Greensand aquifer at Riverhead increased slightly and are now above normal levels. This is due to the amount of effective rainfall recorded during the month of July.
6. Reservoir stocks
Levels at all five of the water company reservoirs declined throughout July. At the end of July, reservoir levels (as % of live capacity) were:
- Notably low at Darwell at 51%
- Below normal at Bough Beech at 67% and at Bewl at 65%
- Normal at Powdermill at 67%
- Above normal at Weir Wood at 93%
7. Environmental impact
Widespread licence hands-off flow restrictions persisted through July in the Medway and Stour catchments. Stour catchment restrictions were lifted during the second half of the month following rainfall. Rother restrictions, imposed throughout June, were also lifted towards the end of July due to improved flows supported by rainfall and groundwater.
Seven fluvial flood alerts were issued in July, one on the 6 July and six on the 18 July.
Author: Groundwater and Hydrology Team, ksl.gwh@environment-agency.gov.uk
Contact details: 0370 850 6506
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.