E. coli, risk of infection?
The maximum temperature for E. coli to survive is dependent on the strain. E. coli from warm areas can easily survive 45 °C and more. The minimum number of E. coli to ingest in order to become ill is also dependent on the strain. Whether you become ill at all is also dependent on the strain. You harbor many billions of E. coli in your digestive tract without becoming ill, so without further information on the released strain, it's really hard to tell.

One of the suggestions from the WHO Guidelines for drinking water quality is to boil the water in order to desinfect it.