South East Rivers Trust (& the Wandle Trust)

Pollution incident in the Hogsmill catchment

Green Lanes Recreation Ground Pollution


On Tuesday 16th October 2018, a pollution incident at Green Lanes Recreation Ground was flagged to us by a member of the local community.

Having visited the site later that day, it looks as if there has been a discharge of sewage from a manhole which has flowed across Green Lane Recreation Ground and potentially into the Hogsmill river.



Above: Sewage matter on the Green Lane Recreation Ground.

Below: The grey colour of sewage dispersed through a woodland.



Thames Water has fenced off the site with signs informing the public to stay away. The site is still clearly contaminated with sewage so we strongly advise that everyone keep clear of this area. Please be vigilant and if you’re walking your dog nearby, it might be worth having them on a lead in the vicinity.

At this time, we do not know the cause of the incident and we have asked both the Environment Agency and Thames Water for more information.

A similar incident took place three years ago, treated by the Environment Agency (EA) as a Category 2 pollution incident (Category 1 being the highest/most serious level and Category 4 the least).


Why is this a problem for the Hogsmill?

Located in south west London, the Hogsmill is a much loved river which flows from Ewell to Kingston where it joins the River Thames. The Hogsmill is classified as a chalkstream, a globally rare habitat with only 200 worldwide. Chalkstreams give rise to a unique set of species that depend on the clean, chalk-purified water and are consequently very sensitive to any decline in water quality.

Sadly, the river suffers from poor water quality, with regular inputs of pollution taking place in its headwaters from two sets of storm tanks, as well as countless misconnections along its length. This is particularly alarming as we have witnessed a decline in the volume of water flowing in the Hogsmill in the last couple of years, which means there is less clean water to dilute such a pollution event.

The Trust is working with the Hogsmill Partnership to better understand and start addressing the poor water quality, as well as increase and enhance river habitats for wildlife.

Have any Question or Comment?

One comment on “Pollution incident in the Hogsmill catchment

Molly Rodford

My dog paddled at the Stepping Stones on either 9 or 10 October. Became very ill over the weekend resulting (starting on Friday) with severe sickness , diarrhoea and dehydration. multiple injection and medications costing £97.00. needed, thankfully today 16th, she is improving with light diet and antibiotics. How sad that a lovely place where children and dogs play can be allowed to be so dangerous.

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