Following the regular water quality tests undertaken by Cam Valley Forum Volunteers over the year 2021/22, from September 2022, Anglian Water monitoring teams are assessing the microbial contamination of the River Cam and its tributaries at the sites we suggested, every week for a year. They are sharing the results with us so we can share them with the wider community.
You can see their most recent results for E.Coli at the key swimming spots here:
When looking at the results, note that it is normal to have some level of bacteria in the river, but levels above 1000 may be “considered elevated”. (Note that this is our interpretation, not Anglian Water’s because there isn’t an official set of guidance values for single readings. We are also told that it is possible to get extremely elevated bacteria concentrations without the possible associated harmful viruses: can happen with algal blooms for instance)
The results show the general pattern, but its also important to realise that it takes a few weeks to get results (because any bacteria need time to grow in the lab), and the water conditions may have changed since the sample was taken. It is also normal for readings to vary a lot. This is why the official standards for bathing water are complicated, and based on multiple readings over a period of time.
The first 12 months data strongly suggests that if we applied for Bathing Water Designation for the Cam at Sheep’s Green, the water quality would be rated as “Poor”.
In the meantime, you can see the results for the levels of E.Coli at key swimming spots on the graph above. You can also see a table of all Anglian Water’s test results for E.Coli here and Enterococci here. These are uploaded roughly once a month.
You must make your own judgement about where and when it is safe for you to swim. For more information, see our advice to swimmers
Test Site Locations
Monitoring sites shown with yellow star
Popular swimming/paddling spots shown with blue star
Water Treatment Works shown with a little tap symbol