2007/20 – Point Samson (Western Australia) – Trihalomethanes, Hardness, Total Dissolved Solids

Point Samson (Western Australia) – Trihalomethanes

2007/8: Point Samson (Western Australia) Trihalomethanes – Total 311μg/L (Highest detection)

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”. Source: https://water.epa.gov/drink/contaminan

Port Samson – Western Australia – Hardness

2008/09: Port Samson (Western Australia) – Hardness 370mg/L (max), 193mg/L (mean)

2010/11 Point Samson (Western Australia) Hardness 220mg/L (max), 175mg/L (mean)

2011/12 Point Samson (Western Australia) Hardness 390mg/L (max), 255mg/L (mean)

2013/14 Point Samson (Western Australia) Hardness 230mg/L (max), 230mg/L (mean)

2014/15 Point Samson (Western Australia) Hardness 310mg/L (max), 285mg/L (mean)

2015/16 Point Samson (Western Australia) Hardness 240mg/L (max), 230mg/L (mean)

2016/17 Point Samson (Western Australia) Hardness 240mg/L (max), 235mg/L (mean)

2017/18 Point Samson (Western Australia) Hardness 200mg/L (max), 170mg/L (mean)

2018/19: Point Samson (Western Australia) Hardness 240mg/L (max), 200mg/L (mean)

2019/20: Point Samson (Western Australia) Hardness 260mg/L (max), 255mg/L (mean)


“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

Point Samson – Western Australia – Total Dissolved Solids

2011/12 Point Samson (Western Australia) Total Dissolved Solids 880mg/L (max), 603mg/L (mean)

2014/15 Point Samson (Western Australia) Total Dissolved Solids 702mg/L (max), 652mg/L (mean)

2019/20: Point Samson (Western Australia) Total Dissolved Solids 607mg/L (max), 595mg/L (mean)


“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