Cryptosporidium is a microorganism found in water that can cause diarrhoeal disease. The most common symptoms are watery diarrhoea and stomach cramps. Other symptoms may include fever, nausea, vomiting and loss of appetite.
Symptoms may last days to weeks. People with a weak immune system may have more severe symptoms that can last for months.
Livestock such as cows and sheep, and sewage can be sources of Cryptosporidium that can infect humans.
Cryptosporidium is not controlled by normal doses of chlorine used to treat drinking water. A high standard of filtration or alternative disinfection, such as ultraviolet light, is needed to control Cryptosporidium.
Microbial health-based targets provide an assessment of the microbial safety of drinking water, including Cryptosporidium. The Australian Drinking Water Guidelines now include guidance on these targets.
Water utilities in NSW are required to implement a drinking water management system that is consistent with the Framework for Managing Drinking Water Quality in the Australian Drinking Water Guidelines. Health-based targets form a small component of the Framework. These targets help inform the appropriate treatment for different water supplies and should be used to prioritise improvements to drinking water safety.
NSW Health and the NSW Department of Climate Change, Energy, the Environment and Water (DCCEEW) have developed an implementation plan for the incorporation of health-based targets in regional NSW. The implementation is based on the NSW Health Cryptosporidium risk assessment. Implementation will take time, particularly if new treatment processes need to be built.
The risk assessment prioritises systems that need the most improvement to meet the Cryptosporidium health-based target. The risk assessment uses a quantitative microbial risk assessment (QMRA) model. The model uses the potential Cryptosporidium sources in the catchment and the existing treatment to assess if the level of treatment is appropriate.
The preliminary results of the model have been shared with each local water utility and NSW DCCEEW. NSW DCCEEW is funding upgrades or additional treatment through the NSW Government Safe and Secure Water Program, based on the priority of the system. Local water utilities may also plan for upgrades or additional treatment based on the risk assessment. Local water utilities should contact their local Public Health Unit if they have questions.
