2020/21 – Calen (Qld) – E.coli, Hardness

2020/21: Calen (Qld) – E.coli.
2020/21: Calen Treated (Qld) – E.coli 49MPN/100mL (max), 4 MPN/100mL (mean)

“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 2011

Calen (Qld)  Hardness

2020/21: Calen Reticulation (Qld) – Hardness 262.41mg/L (max), 158.99mg/L (min)

2020/21: Calen Treated (Qld) – Hardness 259.42mg/L (max), 157.85mg/L (min)


“To minimise undesirable build‑up of scale in hot water systems, total hardness (as calcium
carbonate) in drinking water should not exceed 200 mg/L.

Hard water requires more soap than soft water to obtain a lather. It can also cause scale to form on hot water pipes and fittings. Hardness is caused primarily by the presence of calcium and magnesium ions, although other cations such as strontium, iron, manganese and barium can also contribute.”

Australian Drinking Water Guidelines 2011