2016/17: Potts Hill Customer Supply System:

2016: 1/2292 samples not compliant for E.coli. 99.9% results compliant

https://sydneywater.com.au/web/groups/publicwebcontent/documents/document/zgrf/mdk1/~edisp/dd_095323.pdf

2017: 1/2328 samples not compliant for E.coli. 99.96% results compliant

During the 12-month period from 1 January 2017 to 31 December 2017, there was one E. coli exception in each of Prospect North and Potts Hill Delivery Systems respectively. These delivery systems still complied as at least 98% of the scheduled monthly samples contained no E. coli.

https://www.sydneywater.com.au/web/groups/publicwebcontent/documents/document/zgrf/mtcw/~edisp/dd_170569.pdf

“Coliforms are Gram-negative, non-spore-forming, rod-shaped bacteria that are capable of aerobic and facultative anaerobic growth in the presence of bile salts or other surface active agents with similar growth-inhibiting properties. They are found in large numbers in the faeces of humans and other warm-blooded animals, but many species also occur in the environment.

Thermotolerant coliforms are a sub-group of coliforms that are able to grow at 44.5 ± 0.2°C. E. coli is the most common thermotolerant coliform present in faeces and is regarded as the most specific indicator of recent faecal contamination because generally it is not capable of growth in the environment. In contrast, some other thermotolerant coliforms (including strains of Klebsiella, Citrobacter and Enterobacter) are able to grow in the environment and their presence is not necessarily related to faecal contamination. While tests for thermotolerant coliforms can be simpler than for E. coli, E. coli is considered a superior indicator for detecting faecal contamination…” ADWG