2005/17 – Dunolly (Victoria) – E.coli, Trihalomethanes, Hardness, Total Dissolved Solids, Chloride, Iron, Sodium

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Dunolly (Victoria) – E.coli
24/1/07: Dunolly (Victoria) 1org/100mL. (sample at customer tap)
No known cause – possibly due to low chlorine residual or bird entry.  Laanecoorie WTP operating OK. All possible entry points to the Dunolly tank sealed. Sodium hypochlorite added to Dunolly tank (55 L). Resampling completed showing no further E.Coli.

2010/11 Dunolly E.coli  2/100mL (98.1% samples no e.coli ) (1 positive)

25/11/11 Dunolly E.coli  1/100mL

2012/13 Dunolly E.coli  1/100mL (98.1% samples no e.coli ) (1 positive)


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

Dunolly (Victoria) – Trihalomethanes

2005/06: Dunolly (Victoria) – Trihalomethanes 280μg/L (maximum during year)

17/3/16: Dunolly THM  0.28mg/L

Trihalomethanes Australian Guideline Level 250μg/L (0.25mg/L)

Why and how are THMs formed?
“When chlorine is added to water with organic material, such as algae, river weeds, and decaying leaves, THMs are formed. Residual chlorine molecules react with this harmless organic material to form a group of chlorinated chemical compounds, THMs. They are tasteless and odourless, but harmful and potentially toxic. The quantity of by-products formed is determined by several factors, such as the amount and type of organic material present in water, temperature, pH, chlorine dosage, contact time available for chlorine, and bromide concentration in the water. The organic matter in water mainly consists of a) humic substance, which is the organic portion of soil that remains after prolonged microbial decomposition formed by the decay of leaves, wood, and other vegetable matter; and b) fulvic acid, which is a water soluble substance of low molecular weight that is derived from humus”. US EPA

Dunolly – Victoria – Hardness (maximum detections)

2005/06: Dunolly (Victoria) – Calcium Carbonate 390mg/L (max)

2006/07: Dunolly (Victoria) – Calcium Carbonate 500mg/L (max)

2007/8 Dunolly Hardness 580mg/L

2008/9 Dunolly Hardness 490mg/L

2009/10 Dunolly Hardness 610mg/L

2010/11 Dunolly Hardness 240mg/L

2015/16 Dunolly Hardness 250mg/L

2016/17: Dunolly (Victoria) – Calcium Carbonate 240mg/L (Highest Detection Only)


“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

Dunolly – Victoria – Total Dissolved Solids

2005/06: Dunolly (Victoria) – Total Dissolved Solids 1700 μS/cm (max)

2006/07: Dunolly (Victoria) – Total Dissolved Solids 2400 μS/cm (max)

2007/8 Dunolly Total Dissolved Solids 2800mg/L

2008/9 Dunolly Total Dissolved Solids 2400mg/L

2009/10 Dunolly Total Dissolved Solids 3100mg/L

2010/11 Dunolly Total Dissolved Solids 1600mg/L

2011/12 Dunolly Total Dissolved Solids 1400mg/L

2016/17: Dunolly (Victoria) – Total Dissolved Solids 1600 μS/cm (Maximum Level)


“No specific health guideline value is provided for total dissolved solids (TDS), as there are no
health effects directly attributable to TDS. However for good palatability total dissolved solids
in drinking water should not exceed 600 mg/L.

Total dissolved solids (TDS) consist of inorganic salts and small amounts of organic matter that are dissolved in water. Clay particles, colloidal iron and manganese oxides and silica, fine enough to pass through a 0.45 micron filter membrane can also contribute to total dissolved solids.

Total dissolved solids comprise: sodium, potassium, calcium, magnesium, chloride, sulfate, bicarbonate, carbonate, silica, organic matter, fluoride, iron, manganese, nitrate, nitrite and phosphates…” Australian Drinking Water Guidelines 2011

Dunolly (Victoria) – Chloride (highest levels)

2007/8 Dunolly Chloride 590mg/L

2008/9 Dunolly Chloride 560mg/L

2009/10 Dunolly Chloride 580mg/L

2010/11 Dunolly Chloride 290mg/L

2016/17: Dunolly (Victoria)  Chloride 260mg/L (

“Chloride is present in natural waters from the dissolution of salt deposits, and contamination from effluent disposal. Sodium chloride is widely used in the production of industrial chemicals such as caustic soda, chlorine, and sodium chlorite and hypochlorite. Potassium chloride is used in the production of fertilisers.

The taste threshold of chloride in water is dependent on the associated cation but is in the range 200–300 mg/L. The chloride content of water can affect corrosion of pipes and fittings. It can also affect the solubility of metal ions.

In surface water, the concentration of chloride is usually less than 100 mg/L and frequently below 10 mg/L. Groundwater can have higher concentrations, particularly if there is salt water intrusion.

Based on aesthetic considerations, the chloride concentration in drinking water should not exceed 250 mg/L.

No health-based guideline value is proposed for chloride.” 2011 Australian Drinking Water Guidelines

Dunolly –  Victoria – Iron

2007/8 Dunolly Iron 0.4mg/L

2008/9 Dunolly Iron 0.31mg/L

Based on aesthetic considerations (precipitation of iron from solution and taste),
the concentration of iron in drinking water should not exceed 0.3 mg/L.
No health-based guideline value has been set for iron.

Iron has a taste threshold of about 0.3 mg/L in water, and becomes objectionable above 3 mg/L. High iron concentrations give water an undesirable rust-brown appearance and can cause staining of laundry and plumbing fittings, fouling of ion-exchange softeners, and blockages in irrigation systems. Growths of iron bacteria, which concentrate iron, may cause taste and odour problems and lead to pipe restrictions, blockages and corrosion. ADWG 2011

2007/10 – Dunolly – Sodium

2007/8 Dunolly Sodium 280mg/L

2008/9 Dunolly Sodium 250mg/L

2009/10 Dunolly Sodium 280mg/L

“Based on aesthetic considerations (taste), the concentration of sodium in drinking water
should not exceed 180 mg/L….The sodium ion is widespread in water due to the high solubility of sodium salts and the abundance of mineral deposits. Near coastal areas, windborne sea spray can make an important contribution either by fallout onto land surfaces where it can drain to drinking water sources, or from washout by rain. Apart from saline intrusion and natural contamination, water treatment chemicals, domestic water softeners and
sewage effluent can contribute to the sodium content of drinking water.” ADWG 2011