River Thames E. coli Testing – Wargrave & Shiplake 2026

In 2025 I worked with the HoTWater group in Henley monitoring E. coli levels in the Thames, with results published online and via the HoTWater app.

In 2026, Irene and I plan to extend weekly testing (May–October) to the Wargrave & Shiplake stretch.


We’ll cover setup costs and the first 10 tests. Each additional test costs about £11, and we’d welcome:

• Occasional volunteers to help test

• Contributions to pay for 1 or more tests


Interested? Please email: swimtesting@gmail.com


John & Irene Crawford

Shiplake


Now fully funded for 2026

Comments

Post a Comment

Popular posts from this blog

The Loddon near Wargrave Sewage Treatment Works 19/June/2026

Image
On the 19th June we did a boat trip up the Loddon to near where Wargrave Sewage Treatment Works discharges “treated” sewage. There had been little recent rain, so it is probable that the sewage works were working normally.  The first sample was taken just upstream of the sewage discharge point. This sample would include water from the Loddon and St Patrick’s stream. ⬇️ Small amount of E.coli detected. The next sample was taken a few metres downstream, at the discharge point. ⬇️  E.coli reading = TNTC = too numerous to count. The final sample was taken just before the Loddon joins the Thames. ⬇️ At 6266 cfu/100ml E.coli reading still very high. (Environment Agency advise against swimming if reading is greater than 900 cfu/100ml) An additional sample was also taken on the Thames, just upstream of Shiplake Lock.⬇️ We generally find little or no E.coli here. I swim here.
Read more

Why SWIM in HoTWater?

  SWIM refers to Shiplake and Wargrave Indicative Monitoring (of E.coli in the river) which is associated the HoTWater group . It’s just a light hearted name for a dirty topic. Hopefully, one day, we will be able to SWIM in clean water.
Read more

Demo photo

Image
 The following photo is of a R-Card of unknown origin. It is included for demonstration purposes only. Each blue dot indicates the presence of E.coli in a 1 ml sample      row 1 = 1      row 2 = 12      row 3 = 49      row 4 = 43      row 5 = 45      row 6 = 13 total = 163 Because the accepted unit of measurement is colony forming units of E.coli per 100 ml sample, we multiply 163 x 100 giving 16300 cfu/100ml  In practice we will be examining 3 cards for each test and recording the mean/average of the 3 cards. Because 16300 is greater than 900 the Environment Agency would classify this sample as "poor", and advise against swimming. Me too ( I hope samples from the Thames are not a polluted as this ).
Read more