What are E. coli and Coliforms?

E. coli and coliforms are bacteria that live in the guts of humans and animals. They get into water when there is faecal contamination (poo).

If you find them in your water, it means something is wrong - the water may have been contaminated by sewage, animal waste, or dirty hands.

Why Do We Test for Them?

These bacteria are called 'indicator organisms'. They tell you if the water has been contaminated with poo. If these are present, there could be other harmful bugs too - like viruses or parasites.

E. coli is the most important one to check. If it is there, the water is NOT safe to drink.

How to Test

1. Use a 250ml or 500ml bottle with sodium thiosulphate.
2. Remove any attachments from the tap.
3. Run the tap for 2-3 seconds only.
4. Fill the bottle without touching the tap.
5. Keep at 2-8 degrees C and get to lab within 24 hours.

Understanding Results

| Result | What It Means | What to Do | |---|---|---| | 0 (not detected) | Good - safe | Keep monitoring as normal | | 1-10 CFU/100ml | Check - contamination likely | Investigate source, flush system, re-test | | Over 10 CFU/100ml | Bad - do NOT drink | Stop using water, investigate and fix, disinfect, re-test |

Common Sources of Contamination

• Cross-connections between drinking water and other water (like rain water or heating water)
• Backflow (water flowing the wrong way through pipes)
• Damaged or dirty storage tanks
• Animal or bird contamination of tanks
• Recent pipe repairs without proper disinfection
• Dirty hands touching tap outlets

What to Do If E. coli is Found

1. Stop using the water for drinking immediately.
2. Tell people not to drink the water.
3. Find the source of contamination.
4. Fix the problem (repair pipes, fix tanks, remove cross-connections).
5. Disinfect the affected part of the system.
6. Flush all outlets thoroughly.
7. Re-test after disinfection (wait 2-7 days).
8. Do not put back in use until you get two clear results in a row.