Sydney Water Pollution

Between July and September 1998 the Sydney water crisis involved the contamination of Sydney’s main water supply, the Warragamba Dam, by the microscopic pathogens cryptosporidium and giardia.

Residents were instructed to boil their tap water before use. The contamination was caused by low-quality raw water entering the dam. This was attributed to moderate rainfall in July, followed by heavy rainfall in August and September (after decreasing storage levels since mid-July 1997) which caused pulses of the raw water to enter the dam.

The incident was highly publicised and caused major public alarm. Three successive “boil your water” notices in which residents were instructed to boil their tap water before use affected up to three million residents.

Could this happen again and would the authorities issue a warning to residents to boil their water in time before you have a drink from your tap?