Australian Drinking Water Map

Tea Gardens (New South Wales) – Trihalomethanes

2016/17: Tea Gardens (New South Wales): Trihalomethanes (Reticulation): 303μg/L (max), 222.5μg/L (average)

Tea Gardens water supply system achieved 99.3% of results within ADWG compared to 98.3% during 2015 – 2016. A total of 306 analytes were tested for verification monitoring in Tea Gardens reticulation system. Total trihalomethanes (THMs) were above the guideline value on two occasions. Disinfection by-products are formed when organic matter reacts with chlorine. The long detention time in reservoirs and reticulation system, partly due to low water usage outside holiday periods has contributed to these elevated readings. In response to this, water levels have been reduced in reservoirs when appropriate, and monitoring frequency has been increased.

Midcoast Water: DRINKING WATER QUALITY MANAGEMENT SYSTEM ANNUAL REPORT SUMMARY 2016-2017

2017/18: Tea Gardens (New South Wales): Trihalomethanes (Reticulation): 302μg/L (max), 246.91μg/L (average)

Tea Gardens water supply system achieved 96.0% of water quality results in the reticulation system within ADWG compared to 99.3% during 2016 – 2017. A total of 322 analytes were tested for verification monitoring in Tea Gardens reticulation system.
Results outside ADWG were total trihalomethanes (THMs) on 13 occasions.

Midcoast Water: DRINKING WATER QUALITY MANAGEMENT SYSTEM ANNUAL REPORT SUMMARY 2017-2018

2022/23: THM’s levels problematic particularly after December 2020, with levels frequently breaching ADGW’s. Levels detected were as high as 420ug/L in Dec 20/Jan 21 and Dec 21/Jan 22. During 2022/23 there were 3 breaches to the ADWG’s for THM’s in 2022/23, compared with 24 breaches in 2021/22. There were also 4 breaches to Dichloroacetic Acid guidelines in 2022/23 and two in 2021/22. High levels were due to high Dissolved Organic Carbon in source water due to drought, bushfires and flood.

2022/23: Trihalomethanes 272ug/L (max), 200ug/L (av.)

Midcoast Water: DRINKING WATER QUALITY MANAGEMENT SYSTEM ANNUAL REPORT SUMMARY 2022-2023

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

Tea Gardens (New South Wales) – Dichloroacetic Acid

2022/23: Tea Gardens (New South Wales): Dichloroacetic Acid (Reticulation): 115μg/L (max), 71μg/L (average)

Australian Guidelines Trichloroacetic Acid 0.100mg/L, Dichloroacetic Acid 0.100mg/L

“Chloroacetic acids are produced in drinking water as by-products of the reaction between chlorine and naturally occurring humic and fulvic acids. Concentrations reported overseas range up to 0.16mg/L and are typically about half the chloroform concentration. The chloroacetic acids are used commercially as reagents or intermediates in the preparation of a wide variety of chemicals. Monochloroacetic acid can be used as a pre-emergent herbicide, dichloroacetic acid as an ingredient in some pharmaceutical products, and trichloroacetic acid as a herbicide, soil sterilant and antiseptic.” Australian Drinking Water Guidelines – National Health and Medical Research Council…

There are no epidemiological studies of TCA carcinogenicity in humans. Most of the human health data for chlorinated acetic acids concern components of complex mixtures of water disinfectant by-products. These complex mixtures of disinfectant by-products have been associated with increased potential for bladder, rectal, and colon cancer in humans [reviewed by Boorman et al. (1999); Mills et al. (1998)].” Ref: tmp/Trichloroacetic acid (TCA) CASRN 76-03-9 IRIS US EPA.htm

Tea Gardens (New South Wales)  – Lead

2016/17: Tea Gardens, NSW Lead 0.004mg/L (max), 0.001mg/L (av.)

Lead Guideline reduced from 0.01mg/L to 0.005mg/L in June 2025. “The concentration of lead in water within premises may be higher, especially in older buildings, due to contact of the water with lead-containing plumbing products (enHealth 2021). A review found several Australian and international studies that detected up to 0.162 mg/L of lead in drinking water due to leaching from lead-containing plumbing materials including taps and lead service lines, suggesting that leaching of lead from lead-containing plumbing materials can be substantial (SLR 2023)… Based on health considerations, the concentration of lead in drinking water should not exceed 0.005 mg/L.”

2016/23 – Tea Gardens (New South Wales) – Trihalomethanes, Dichloroacetic Acid, Lead

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Tea Gardens (New South Wales) – Trihalomethanes 2016/17: Tea Gardens (New South Wales): Trihalomethanes (Reticulation): 303μg/L (max), 222.5μg/L (average) Tea Gardens water supply system achieved 99.3% of results within ADWG compared to 98.3% during 2015 – 2016. A total of 306 analytes were tested for verification monitoring in Tea Gardens reticulation system. Total trihalomethanes (THMs) were above the guideline value on two occasions. Disinfection by-products are formed when organic matter reacts with chlorine. The long detention time in reservoirs and reticulation system, partly due to low water usage outside holiday periods has contributed to these elevated readings. In response to this, water levels have been reduced in reservoirs when appropriate, and monitoring frequency has been increased. Midcoast Water: DRINKING WATER QUALITY MANAGEMENT SYSTEM ANNUAL REPORT SUMMARY 2016-2017 2017/18: Tea Gardens (New South Wales): Trihalomethanes (Reticulation): 302μg/L (max), 246.91μg/L (average) Tea Gardens water supply system achieved 96.0% of water quality results in the reticulation system within ADWG compared to 99.3% during 2016 – 2017. A total of 322 analytes were tested for verification monitoring in Tea Gardens reticulation system. Results outside ADWG were total trihalomethanes (THMs) on 13 occasions. Midcoast Water: DRINKING WATER QUALITY MANAGEMENT SYSTEM ANNUAL REPORT SUMMARY 2017-2018 2022/23: THM’s levels problematic particularly after December 2020, with levels frequently breaching ADGW’s. Levels detected were as high as 420ug/L in Dec 20/Jan 21 and Dec 21/Jan 22. During 2022/23 there were 3 breaches to the ADWG’s for THM’s in 2022/23, compared with 24 breaches in 2021/22. There were also 4 breaches to Dichloroacetic Acid guidelines in 2022/23 and two in 2021/22. High levels were due to high Dissolved Organic Carbon in source water due to drought, bushfires and flood. 2022/23: Trihalomethanes 272ug/L (max), 200ug/L (av.) Midcoast Water: DRINKING WATER QUALITY MANAGEMENT SYSTEM ANNUAL REPORT SUMMARY 2022-2023 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 Tea Gardens (New South Wales) – Dichloroacetic Acid 2022/23: Tea Gardens (New South Wales): Dichloroacetic Acid (Reticulation): 115μg/L (max), 71μg/L (average) Australian Guidelines Trichloroacetic Acid 0.100mg/L, Dichloroacetic Acid 0.100mg/L “Chloroacetic acids are produced in drinking water as by-products of the reaction between chlorine and naturally occurring humic and fulvic acids. Concentrations reported overseas range up to 0.16mg/L and are typically about half the chloroform concentration. The chloroacetic acids are used commercially as reagents or intermediates in the preparation of a wide variety of chemicals. Monochloroacetic acid can be used as a pre-emergent herbicide, dichloroacetic acid as an ingredient in some pharmaceutical products, and trichloroacetic acid as a herbicide, soil sterilant and antiseptic.” Australian Drinking Water Guidelines – National Health and Medical Research Council… There are no epidemiological studies of TCA carcinogenicity in humans. Most of the human health data for chlorinated acetic acids concern components of complex mixtures of water disinfectant by-products. These complex mixtures of disinfectant by-products have been associated with increased potential for bladder, rectal, and colon cancer in humans [reviewed by Boorman et al. (1999); Mills et al. (1998)].” Ref: tmp/Trichloroacetic acid (TCA) CASRN 76-03-9 IRIS US EPA.htm Tea Gardens (New South Wales)  – Lead 2016/17: Tea Gardens, NSW Lead 0.004mg/L (max), 0.001mg/L (av.) Lead Guideline reduced from 0.01mg/L to 0.005mg/L in June 2025. “The concentration of lead in water within premises may be higher, especially in older buildings, due to contact of the water with lead-containing plumbing products (enHealth 2021). A review found several Australian and international studies that detected up to 0.162 mg/L of lead in drinking water due to leaching from lead-containing plumbing materials including taps and lead service lines, suggesting that leaching of lead from lead-containing plumbing materials can be substantial (SLR 2023)… Based on health considerations, the concentration of lead in drinking water should not exceed 0.005 mg/L.”