There’s no easy way to put this. The E.coli testing kit we talked about getting last month has proved its worth. It has also proved there’s something wrong with the Tiffey.
The Environment Agency standard for safe bathing waters is 9 CFU per ml of E.coli. That is nine colony-forming units per millilitre. The much-used pool below Becketswell Bridge failed that standard in each of our four tests so far, and at its worst – on a warm sunny day after heavy rain – it was up at 112 CFU/ml.
It wasn’t the worst spot, which goes to the area on the Lizard where a footbridge used to cross the Tiffey: 251 CFU/ml. That is up with the Thames at its worst. This particular spot on our river is now down to a happier 5, but questions remain: where is the pollution coming from? What can we do? What should we do?
The first thing to do is report to the Environment Agency hotline the very next time it hits those figures again. The second is to continue testing. We plan to do this fortnightly during the winter – as well as in response to any news of smells, unsightly material in the water, grey-white sewage fungus or mass algal growth. In the spring and summer, we will try to test paddling sites weekly.

Councillor Suzanne Nuri-Nixon, who helped us purchase the equipment, says the public will need to be informed. “We’re working with Greening Wymondham on ways to do this, “ she says, “including data by the Tiffey bridges where people go into the water, and online. We’re taking this seriously.”
The advice from the Environment Agency website is simple. No ban on entering the water, but basic precautions if the levels are higher than the 9CFU/ml. These precautions are to cover up cuts if you must go in, wash your hands before eating – and, we’d add, if very contaminated, shower both yourselves and your dogs.
In Wymondham, the Tiffey is too shallow to swim in but there are bathing places further downstream. Unless your river has designated bathing water status, the Agency is under no obligation to test.
As for tracing the source, the high Lizard level is above the two Anglian Water pumping stations and the sewage works. Other culprits could be leaking or broken septic tanks, field run-off, a broken drain – but whatever it is seems sporadic, making it harder to hunt down.

Anglian Water acknowledged earlier this year that they had released untreated wastewater into the Tiffey from both pumping stations and the sewage works, which they are allowed to do under licence during prolonged heavy rainfall. Residue from that could also be washed out of areas affected by subsequent heavy rainfall.
Greening Wymondham will keep testing and we hope to expand the current 7 sites downstream. We are hampered only by a lack of people. We currently have four volunteers, taking it in turns fortnightly to collect and test for a range of pollutants like nitrate and phosphate as well as, now, E. coli.
If you’d like to join us and feel you could commit to collect or test next year, please email us at greening.wymondham@gmail.com. And let us know if you have concerns, advice or questions.