2016/23 – Padthaway (South Australia) – Hardness, Chloride, Chlorate, Sodium, Total Dissolved Solids

Padthaway – South Australia – Hardness

September 13 2016: Padthaway (South Australia) – Calcium Hardness 397mg/L

November 8 2016: Padthaway (South Australia) – Calcium Hardness 429mg/L

March 27 2017: Padthaway (South Australia) – Calcium Hardness 372mg/L

June 20 2017: Padthaway (South Australia) – Calcium Hardness 370mg/L

2018/19: Padthaway (South Australia) – Hardness 397mg/L (max), 387.25mg/L (av.)

2018/19: Padthaway (South Australia) – Hardness as CaCO3 598mg/L (max), 583mg/L (av.)

2019/20: Padthaway Total Hardness as CaCO3 605mg/L (max), 590.75mg/L av.

2019/20: Padthaway Calcium Hardness as CaCO3 405mg/L (max), 391.5mg/L av.

2022/23: Padthaway Calcium Hardness as CaCO3 410mg/L (max), 391mg/L av.


“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

Padthaway (South Australia) – Chloride

September 13 2016 Padthaway (South Australia)  Chloride 619mg/L

November 8 2016 Padthaway (South Australia)  Chloride 620mg/L

March 27 2017 Padthaway (South Australia)  Chloride 607mg/L

June 20 2017 Padthaway (South Australia)  Chloride 618mg/L

2018/19: Padthaway (South Australia) Chloride 645mg/L (max), 631.75mg/L (av.)

2019/20: Padthaway Chloride 664mg/L (max). 645.5mg/L av.

2022/23: Padthaway Chloride 693mg/L (max). 677mg/L av.

“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

2016/17: Padthaway (South Australia) – Chlorate

23/8/16: Padthaway (South Australia) – Chlorate 0.44mg/L

16/5/17: Padthaway (South Australia) – Chlorate 0.36mg/L

Chlorite: ADWG Health 0.3mg/L.

Chlorite and chlorate are disinfection by-products of chlorine dioxide disinfection process.

“… industry are having serious problems meeting chlorite/chlorate limits that were proposed in the new Australian Drinking Water Guidelines, especially for disinfection in long distance pipelines that are dosed with sodium hyptochlorite” pers comm 18/5/11.

“Chlorite occurs in drinking water when chlorine dioxide is used for purification purposes. The
International Agency for Research on Cancer (IARC) has concluded that chlorite is not classifiable as carcinogenic to humans and is listed in the Group 3 category. Changes in red blood vessels due to oxidative stress are a major concern with excessive levels of Chlorite in drinking water. According to the US EPA, potential health problems for people drinking Chorite above safe drinking water guideline include: Anemia in infants and young children and nervous system effects.” https://water.epa.gov/drink/contaminants/index.cfm

“Chlorine dioxide (chlorite) is rarely used as a disinfectant in Australian reticulated supplies.
When used, the chlorite residual is generally maintained between 0.2mg/L and 0.4mg/L. It is
particularly effective inthe control of manganese-reducing bacteria. Few data are available on
chlorate levels in Australian water supplies….Chlorine dioxide, chlorite, and chlorate are all
absorbed rapidly by the gastrointestinal tract into blood plasma and distributed to the major
organs. All compounds appear to be rapidly metabolised. Chlorine dioxide has been shown to
impair neurobehavioural and neurological development in rats exposed before birth. Experimental studies with rats and monkeys exposed to chlorine dioxide in drinking water have shown some evidence of thyroid toxicity; however, because of the studies’ limitations, it is difficult to draw firm conclusions (WHO 2005) The primary concern with chlorite and chlorate is oxidative stress resulting in changes in red blood cells. This end point is seen in laboratory animals and, by analogy with chlorate, in humans exposed to high doses in poisoning incidents (WHO 2005).” Australian Drinking Water Guidelines – National Health and Medical Research Centre

“…Subchronic studies in animals (cats, mice, rats and monkeys) indicate that chlorite and chlorate cause haematological changes (osmotic fragility, oxidative stress, increase in mean corpuscular volume), stomach lesions and increased spleen and adrenal weights… Neurobehavioural effects (lowered auditory startle amplitude, decreased brain weight and decreased exploratory activity) are the most sensitive endpoints following oral exposure to chlorite…” https://www.hc-sc.gc.ca/ewh-semt/pubs/water-eau/chlorite-chlorate/indexeng.
php#sec10_1Guidelines for Canadian Drinking Water Quality.

Padthaway (South Australia) – Sodium

5/9/16 Padthaway  Sodium 314mg/L

28/11/16 Padthaway Sodium 373mg/L

20/3/17 Padthaway Sodium 316mg/L

13/6/17 Padthaway Sodium 308mg/L

2018/19: Padthaway (South Australia) 367mg/L (max), 346.25mg/L (av. 2018/19)

11/5/20: Padthaway Sodium 360mg/L (max), 339.25mg/L (av. 2019/20)

8/5/23: Padthaway Sodium 377mg/L (max), 346.5mg/L (av.2022/23)

“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

Padthaway (South Australia) – Total Dissolved Solids

2018/19: Padthaway (South Australia) Total Dissolved Solids 1600mg/L (max), 1600mg/L (av)

2019/20: Padthaway Total Dissolved Solids (by EC) 1650mg/L (max), 1595mg/L av.

2022/23: Padthaway Total Dissolved Solids (by EC) 1680mg/L (max), 1662.5mg/L av.


“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