2012/21 – Nepabunna (South Australia) – E.coli, Arsenic, Chloride, Zinc, Iron, Sodium, Sulphate, Total Dissolved Solids, Hardness, Turbidity, Lead

Nepabunna (South Australia) – E.coli
22 October 2014: Nepabunna (South Australia) 100cfu/100mL

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

Nepabunna (South Australia) – Arsenic

18/8/20: Nepabunna (South Australia)Arsenic 0.0873mg/L (Potable System-Non Potable Zone)

Arsenic: Australian Drinking Water Guideline = 0.01mg/L

Arsenic is bioaccumulative and symptoms may take 10-15 years to develop after expsoure at high levels. Drinking water can be contaminated with inorganic arsenic through wind blown dust, leaching or runoff from soil, rocks and sediment. Groundwater sources such as bores will usually have higher arsenic levels than surface water. In major Australian reticulated water supplies concentrations of arsenic range up to 0.015mg/L, with typical values less than
0.005mg/L. https://www.health.qld.gov.au/ph/documents/ehu/2676.pdf

Nepabunna (South Australia) – Chloride

7 August 2012: Nepabunna (South Australia) Chloride 319mg/L

29 October 2013: Nepabunna (South Australia) Chloride 456mg/L

31/7/19: Nepabunna (fire hydrant) (South Australia) Chloride 340mg/L (potable/non-potable)

“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

Nepabunna (South Australia) – Zinc

7 August 2012: Nepabunna (South Australia) – Zinc 3.309mg/L

31/7/19: Nepabunna (South Australia) Zinc 2.564mg/L (potable/non-potable)

26/8/21: Nepabunna TS Rain Water (Flushing Main) Zinc 3.112 mg/L

Based on aesthetic considerations (taste), the concentration of zinc in drinking water should
be less than 3 mg/L. No health-based guideline value is proposed for zinc.

Zinc is widely distributed and occurs in small amounts in almost all rocks, commonly as the sulfide. It is used as a coating to prevent corrosion of iron and steel products, and in the manufacture of brass. Zinc oxide is an important component in the manufacture of paint and rubber products, including tyres.

In surface and ground waters, the concentration of zinc from natural leaching is usually less than 0.01 mg/L. Tap water can contain much higher concentrations as a result of corrosion of zinc-coated pipes and fittings. Zinc concentrations in galvanised iron rainwater tanks are typically 2 mg/L to 4 mg/L but have been reported as high as 11 mg/L.

Taste problems can occur if the zinc concentration in drinking water exceeds 3 mg/L. Water with a zinc concentration above 5 mg/L tends to be opalescent, develops a greasy film when boiled, and has an undesirable dry ‘metallic’ taste. Zinc is present in plant and animal tissues, and food is the major source of zinc intake. Drinking water usually makes a negligible contribution to total intake. 2011 ADWG

Nepabunna (South Australia) – Iron

7 August 2012: Nepabunna (South Australia) Iron 69.19mg/L

29 October 2013: Nepabunna (South Australia) Iron 14.53mg/L

31/7/19: Nepabunna (fire hydrant) (South Australia) Iron 2.197mg/L (potable/non-potable)

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

2014/16 – Nepabunna – Sodium

30 July 2014: Nepabunna (South Australia) – Sodium 300mg/L

27 July 2016: Nepabunna (South Australia) – Sodium 262mg/L

26/11/19: Nepabunna (fire hydrant) (South Australia) Sodium 294mg/L (potable/non-potable)

“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

2012/13 – Nepabunna (South Australia) – Sulphate

7 August 2012: Nepabunna (South Australia)  Sulphate 399mg/L

29 October 2013: Nepabunna  (South Australia) Sulphate 378mg/L

31/7/19: Nepabunna (fire hydrant) (South Australia) Sulphate 378mg/L (potable/non-potable)

“Based on aesthetic considerations (taste), the concentration of sulfate in drinking water
should not exceed 250 mg/L. Purgative effects may occur if the concentration exceeds 500 mg/L.

Sulfate occurs naturally in a number of minerals, and is used commercially in the manufacture of numerous products including chemicals, dyes, glass, paper, soaps, textiles, fungicides and insecticides. Sulfate, including sulfuric acid, is also used in mining, pulping, and the metal and plating industries. Barium sulfate is used as a lubricant in drilling rigs for groundwater supply.
In the water industry, aluminium sulfate (alum) is used as a flocculant in water treatment, and copper sulfate is used for the control of blue-green algae (cyanobacteria) in water storages.
The highest concentrations reported in drinking water overseas are from groundwater supplies where the presence of sulfate is due to natural leaching from rocks. Concentrations have been reported up to 2200 mg/L. In source waters, concentrations are typically less than 100 mg/L.
The taste threshold for sulfate is in the range 250–500 mg/L.” ADWG 2011

2012/16 – Nepabunna (South Australia) – Total Dissolved Solids

August 2012 – July 2016: 1460mg/L (average from 5 detections. All above ADWG)

31/7/19: Nepabunna (fire hydrant) (South Australia)Total Dissolved Solids 1480mg/L (potable/non-potable)


“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.

Nepabunna (South Australia) – Hardness

2012/16: Nepabunna (South Australia) – Hardness average 745.8mg/L (5 detections out of 5 above guideline)

31/7/19: Nepabunna (fire hydrant) (South Australia) Hardness 479mg/L (potable/non-potable)

31/7/19: Nepabunna (fire hydrant) (South Australia) Hardness 729mg/L (potable/non-potable)


“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.”

Nepabunna (South Australia) – Turbidity

31/7/19: Nepabunna (fire hydrant) (South Australia)Turbidity 31 NTU (potable/non-potable)

Chlorine-resistant pathogen reduction: Where filtration alone is used as the water treatment
process to address identified risks from Cryptosporidium and Giardia, it is essential
that filtration is optimised and consequently the target for the turbidity of water leaving
individual filters should be less than 0.2 NTU, and should not exceed 0.5 NTU at any time
Disinfection: A turbidity of less than 1 NTU is desirable at the time of disinfection with
chlorine unless a higher value can be validated in a specific context.

Aesthetic: Based on aesthetic considerations, the turbidity should not exceed 5 NTU at the
consumer’s tap.

Nepabunna (South Australia) – Lead

22/9/21: Nepabunna Rain Water Flushing Main Lead 0.0287mg/L (max) 0.018mg/L (av.)

No lead detections elsewhere in the system or at the WTP on this date or in previous weeks. It was determined that this was a localised issue at the two sample taps. Resample did not detect lead and previous samples at  these points had not detected lead. Sample points were replaced with dedicated Ned Kelly sample points and lead has not been detected since.

Lead Australian Drinking Water Guideline 0.01mg/L

“… Lead can be present in drinking water as a result of dissolution from natural sources, or from household plumbing systems containing lead. These may include lead in pipes, or in solder used to seal joints. The amount of lead dissolved will depend on a number of factors including pH, water hardness and the standing time of the water.

Lead is the most common of the heavy metals and is mined widely throughout the world. It is used in the production of lead acid batteries, solder, alloys, cable sheathing, paint pigments, rust inhibitors, ammunition, glazes and plastic stabilisers. The organo-lead compounds tetramethyl and tetraethyl lead are used extensively as anti-knock and lubricating compounds in gasoline…ADWG 2011