FAQ / Contaminated tap water

Contaminated tap water

During a water boil notice, your tap  water may contain bugs that can make people sick, for example causing vomiting or diarrhoea. Our routine water quality tests look for E.coli which, if found, indicates that there are bugs (bacteria or protozoa such as cryptosporidium or giardia) in the water that could cause human illness. Boiling water kills all of these bugs.


E.coli is a type of bacteria that normally lives in the intestines (gut) of people and animals. Although some E.coli can cause illness, finding this bug in the water is a marker that there could be other bugs present in the water. 

What these bugs are will depend on what has caused the contamination.  However, these bugs are likely to cause symptoms such as: stomach cramps, diarrhoea, gas, loss of appetite/nausea, vomiting, fatigue, muscle aches and fever. Symptoms can last from a few days to more than a week.


Protozoa is a type of parasite. Common types of protozoa found in contaminated water are cryptosporidium and giardia. They can cause diarrhoea.