Testing on the Thames

For Maidenhead resident Sean Haywood, the River Thames has been a source of joy for nearly 20 years. Swimming first in Jubilee River, and then the Thames, Sean and his wife are part of a community of wild swimmers who love the water. 

 But just a few kilometres from their swim spot near Boulters Lock is the Marlow Sewage Works. Sean knew that untreated sewage spills were contaminating the water, but not when or how dangerous it was to their health. He asked Thames Water if they could be notified about untreated spills. But after months of dragged-out, minimal correspondence, he decided to take matters into his own hands.  

 The group needed water quality information throughout the year. And they weren’t getting it from Thames Water. 

Sick of waiting for Thames Water, who were providing no guidance on what was in the water – or the risk to swimmers’ health – Sean and a small group of dedicated volunteers started bacterial testing. They test weekly for two main types of bacteria: E. coli and intestinal enterococci. Because these bacteria thrive in the human gut, they’re often found in untreated sewage and used to flag pollution in the water.

And Sean and the group test year-round, unlike the EA who only test in the 20 week bathing season (15 May to the end of September). Testing all 12 months is critical to building a full picture of pollution.

“The only way for us to monitor any issues is by measuring the E. coli count ourselves. The official bathing season dates set by Defra are quite arbitrary, and since we swim well before and after those dates, we need water quality information throughout the year.”

They’re not the only community taking matters into their own hands. So, we asked Sean what role citizen science should play in understanding water quality:

“There’s an ongoing role for Citizen Scientists for river and lake testing, even once the authorities finally get their act together. We are passionate about our communities and will hold regulators to account when their results differ from ours.

If DEFRA and the EA were more inclusive, they could enlist local communities and reduce costs by training local Citizen Scientists to conduct regulatory testing.”

Since starting testing, Sean has linked up with other citizen scientists to share data and build a stronger picture of the Thames’ water quality. They’ve linked all their data on the Water Testing River Thames website. 

You can see the data for yourself here: Water Testing River Thames

 “Connecting communities has been essential for sharing information and motivating one another. We’re already detecting patterns in test results, leading to further investigations into other pollution sources entering our stretch of river undetected.”