Water crowfoot

Thames Water Water Quality Update Autumn 2022

January 30, 2023

Read Thames Water’s Autumn 2022 Water Quality Update – Kennet and Tributaries. Thames Water will circulate updates quarterly to keep you updated with the latest water quality data from the catchment.

Surface Water Summary


There has been no metaldeyde at sample points between December 2021 and November 2022, and TW do not expect to see any detections going forward as metaldehyde is now banned for outside use.


Elevated levels of propyzamide (>0.1 μg/l) we seen in the Enborne in February and March. TW have not seen significant amounts of propyzamide at any of the sample points since March.


No carbetamide was detected at any of the sample points in the Kennet catchment between January and November 2022, apart from a low detection of 0.027μg/l in the Enborne in September.


Groundwater Summary


Nitrate concentrations in groundwater have remained consistently below the DWS in the abstractions in the Ogbourne, Axford, Hungerford and Leckhampstead catchments in the last year. Marlborough recorded a concentration of 63.96mg/l in January 2022; however, TW believe this result is anomalous, and concentrations have been below the DWS since. Ashdown Park and Fognam Down have consistently recorded concentrations of 45-52mg/l from December 2021 to August 2022, with Ashdown Park recording above the DWS from February to May 2022. This has decreased since September 2022, with no abstraction recording concentrations >45mg/l.