Microbiological contamination is when unwanted micro-organisms — bacteria, viruses, fungi or parasites — end up in water, food or an environment where they have no business being. It is the most immediate health risk where water is concerned.
The main sources
- Faecal contamination of human or animal origin.
- Ingress into the network during a pressure drop or building work.
- Stagnation in a tank or a dead leg.
- Biofilm developed on pipe walls.
How it is detected
Pathogens are not each looked for individually: indicator organisms are used instead, mainly Escherichia coli and enterococci. Their presence signals contamination of faecal origin, and therefore a possible risk of other pathogens.
Biofilm, the quiet enemy
Micro-organisms organise themselves into an adherent layer on internal walls. Protected within that matrix, they resist disinfectants far better and continuously reseed the water. That is why a simple chlorine shock is not always enough.
How to protect against it
Appropriate disinfection (chlorine, ozone or UV), maintaining a residual as far as the most distant points, removing dead legs, scheduled tank maintenance and regular testing. Structural prevention always costs less than managing an incident.