Quarterly Drinking Water Quality Report Prospect South Delivery System 1 January 2021 to 31 March 2021 29 April 2021

Quarterly Drinking Water Quality Report | Prospect South Delivery System 1 January 2021 to 31 March 2021 1

This report summarises a selection of health characteristics and Your water quality key aesthetic (look, taste and smell) characteristics. We take water samples from the catchments, at the inlet and outlet of Drinking water management water filtration plants, from the reservoirs and from about 720 We supply you with high quality, safe drinking water – managed under customers’ front garden taps. our drinking water quality management system. Our water is among the Our laboratories use internationally accredited methods for all our world’s best! testing. WaterNSW manages Sydney’s catchments to provide the best quality The tables in this report present water quality data from the analysis of water for us to treat. We treat your water by first filtering it, then water samples we collect at various stages of the water supply chain, disinfecting it. This is called the ‘multiple-barrier’ approach. We from raw water sources, through treatment to the water supplied to your continuously monitor these steps to ensure our systems are working as tap. expected.

During this quarter, our monitoring confirmed that the drinking water we delivered to you was safe and of high quality.

Testing for water quality Our aim is to provide you with high quality, safe drinking water treated to meet the Australian Drinking Water Guidelines. Our Drinking Water Quality Management System applies the frameworks to manage drinking water quality, and testing water quality is one part of this system. We test your water for up to 70 different characteristics including:

• taste

• colour • odour • micro-organisms • chemical content.

Quarterly Drinking Water Quality Report | Prospect South Delivery System 1 January 2021 to 31 March 2021 2

Our Drinking Water Quality We use a number of steps to ensure your tap Management System water is high quality and safe to drink. Daily performance results can be found on our The Australian Drinking Water Guidelines Framework for Management website. of Drinking Water Quality uses a preventive risk management approach that encompasses all the steps in water production from the catchment to the customer. Sydney Water works collaboratively with WaterNSW to ensure that the best possible water quality is supplied to our customers. Sydney Water and WaterNSW apply a multi-barrier approach to ensure the water supply is safe. Some of the steps or ‘barriers’ we use to manage water quality are:

• Protecting water catchments (e.g. lakes, rivers and reservoirs) • Selecting the best available source of water • Filtering the water at water filtration plants • Adding chlorine at our water filtration plants and in the network to ensure your water is free of harmful pathogens • Adding fluoride to support dental health. We monitor these different steps constantly at critical control points to ensure that your drinking water remains safe and of high quality. You can see current results for these points on our Daily Drinking Water Quality report. We monitor water quality to verify that these barriers are working. The results in the remainder of this report are considered ‘verification results’.

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Water quality test results At your tap The data we present here isn’t exhaustive but show the characteristics of water which we Most health guideline values for chemicals are based on a lifetime of exposure. The Australian Drinking Water Guidelines therefore regularly test for which the Australian Drinking recognise that occasionally there may be health or aesthetic related test Water Guidelines has set a health and/or results that fall outside the guideline values and that these results are aesthetic guideline value. not necessarily an immediate threat to health. For most characteristics, the guidelines do not require 100% of results to fall within the guideline values. Sydney Water has a number of areas it delivers water to. We call these Delivery Systems. Our compliance to the guidelines is measured for each Delivery System and is calculated over a 12-month period using the following long-term performance measures:

• For the indicator bacterium Escherichia coli (E. coli), at least 98% of scheduled samples must contain no E. coli. In addition to continuous online monitoring of filter performance, this verifies that our filtration and disinfection processes were effective in removing bacteria from the water initially and that the system used to deliver water to your tap remains clean. • For health-related chemical characteristics, the upper bound of the 95% confidence interval for the 95th percentile must be less than the guideline value. • For aesthetic characteristics, the upper bound of the 95% confidence interval for the mean must be less than the guideline value. The following tables show data for the customer supply systems that we use to measure Sydney Water’s performance against the long-term health and aesthetic guideline values. More data including typical ranges over a longer period can be found in the Safe Drinking Water and Water Analysis pages on the Sydney Water website.

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Table 1 Water Quality Health Characteristics for the Prospect South Delivery System Characteristic Units of ADWG No. of No. of Long-term % of test results Met long-term measure health samples exceptions performance complying with performance guideline 1 Apr 2020 to measure the guideline measure value 31 Mar 2021 (assessment over 12-month period)

E. coli orgs/100 mL Should not 762 1 At least 98% of 99.87% Yes be detected test results <1 in 100 mL sample fluoride mg/L 1.5* 172 0 At least 95% of 100% Yes test results 0.90 to 1.50 mg/L free chlorine mg/L 5 762 0 The 95th percentile value is less than Yes the respective ADWG health monochloramine mg/L 3 762 0 guideline value Yes antimony^ mg/L 0.003 8 0 Yes cadmium^ mg/L 0.002 8 0 Yes cyanide^ mg/L 0.08 2 0 Yes copper mg/L 2 28 0 Yes lead mg/L 0.01 28 0 Yes

nitrate as NO3 mg/L 50 28 0 Yes

nitrite as NO2 mg/L 3 28 0 Yes nickel^ mg/L 0.02 8 0 Yes sulfate^ mg/L 500 4 0 Yes chromium^ mg/L 0.05 (as 8 0 Yes CrVI)** manganese mg/L 0.5 120 0 Yes

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Characteristic Units of ADWG No. of No. of Long-term % of test results Met long-term measure health samples exceptions performance complying with performance guideline 1 Apr 2020 to measure the guideline measure value 31 Mar 2021 (assessment over 12-month period) n-nitrosodimethylamine^ mg/L 0.0001 2 0 Yes total trihalomethanes mg/L 0.25 57 0 The 95th percentile statistic Yes calculated for combined customer supply system and WFP less than 0.25 mg/L

* The long-term fluoride performance for each delivery system in this table is based on customer tap data. We target a value of 1 mg/L. The ADWG specifies a guideline value for fluoride of <1.5 mg/L. The NSW Code of Practice for Fluoridation of Public Water Supplies sets a target that each year >95% of all routine fluoride samples (both treated water from WFPs and customer taps) fall within the concentration range of 0.90 to 1.50 mg/L. ** The ADWG sets a guideline value for hexavalent chromium (Cr(VI)) however Sydney Water measures total chromium which includes hexavalent chromium. ^ Insufficient data to calculate 95th percentile. Abbreviations: ADWG = Australian Drinking Water Guidelines; E. coli = Escherichia coli; mg/L = milligrams per litre; orgs/100 mL = organisms per 100 millilitres.

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Table 2 Water Quality Aesthetic Characteristics for the Prospect South Delivery System Characteristic Units of ADWG aesthetic No. of samples Average Long-term performance measure Met long-term measure guideline value 1 Apr 2020 to result (assessment over 12-month period) performance 31 Mar 2021 measure iron mg/L 0.3 120 0.009 Average of test results less than Yes respective ADWG aesthetic guideline aluminium mg/L 0.2 29 0.012 value Yes manganese mg/L 0.1 120 0.004 Yes copper mg/L 1 28 0.026 Yes zinc mg/L 3 28 0.003 Yes ammonia as mg/L 0.50 28 0.280 Yes NH3 turbidity NTU 5 762 0.11 Yes true colour HU 15 28 3 Yes dissolved % saturation greater than 85% 28 109.9 Yes oxygen hardness mg/L 200 28 57.8 Yes (total) flavour rating* acceptable 1 2 Average rating of 1, 2 or 3 Yes odour rating* acceptable 1 2 Yes pH pH units 6.5-8.5 761 7.9 Average of test results between Yes 6.5 - 8.5 pH units

*Rated by a panel on a scale from 1 to 5. Ratings of 1, 2 and 3 are generally acceptable to most people while ratings of 4 and 5 are generally not acceptable.  True colour is measured at 400 nm wavelength. Abbreviations: ADWG = Australian Drinking Water Guidelines; HU = Hazen Units; mg/L = milligrams per litre; NTU = nephelometric turbidity units

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We also test for a range of other water characteristics at your tap over Parameter Range (10th – Units the course of the year. In Table 3 we’ve summarised the typical values 90th Percentile) for a range of characteristics for your area, note that these values are or Average intended to provide an approximate guide, and that all compliance- related values are provided in Table 1 and Table 2. Disinfection by-products trihalomethanes 0.080 mg/L

Table 3 Typical values for your area Inorganic chemicals aluminium <0.005 - 0.019 mg/L Parameter Range (10th – Units th 90 Percentile) ammonia (as NH3) <0.001 - 0.440 mg/L or Average arsenic 0.0002 - 0.003 mg/L Physical Characteristics cadmium <0.0001 mg/L true colour 2 - 4 TCU or HU antimony <0.0003 mg/L turbidity 0.08 - 0.14 NTU calcium 10.7 - 17.5 mg/L total dissolved solids 124 - 164 mg/L chloride 29.0 - 31.5 mg/L pH 7.7 - 8.0 pH units chromium <0.0002 mg/L conductivity 20.9 - 24.9 mS/m copper 0.009 - 0.044 mg/L total hardness 44 - 65 mg CaCO3 /L cyanide <0.005 mg/L calcium hardness 31 - 44 mg CaCO3 /L fluoride 1.00 mg/L magnesium hardness 19 - 29 mg CaCO3 /L iron <0.005 - 0.013 mg/L alkalinity 37.9 - 57.0 mg CaCO3 /L lead 0.0001 - 0.0004 mg/L temperature 15.1 - 23.1 degrees C nickel 0.0005 - 0.0008 mg/L dissolved oxygen 101.7 - 122.0 % saturation magnesium 4.02 - 6.40 mg/L Disinfectants manganese 0.0014 - 0.0067 mg/L free chlorine 0.09 mg/L mercury <0.00001 mg/L monochloramine 1.09 mg/L

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Parameter Range (10th – Units Parameter Range (10th – Units 90th Percentile) 90th Percentile) or Average or Average

nitrate (as NO3) 0.10 - 0.77 mg/L sodium 14.5 - 19.0 mg/L

nitrite (as NO2) <0.001 - 0.124 mg/L sulfate 8.7 - 11.0 mg/L phosphorous 0.002 - 0.003 mg/L zinc 0.001 - 0.004 mg/L potassium 2.60 - 3.43 mg/L Organic compounds

reactive silica (as SiO2) 1.9 - 4.3 mg/L chlorinated, polynuclear aromatic, Not detected aromatic hydrocarbons selenium <0.0002 mg/L chlorophenols Not detected silver <0.0001 mg/L pesticides Not detected

At the treatment plant The water at your tap is treated at our Prospect Water Filtration Plant. Results for key water quality characteristics which we test are We monitor the quality of the untreated water entering our filtration presented here for the Prospect Water Filtration Plant. plants to understand how much treatment is needed and to verify the quality of treated water leaving the plant for a range of water quality characteristics.

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Table 4 Treated water quality characteristics at Prospect Water Filtration Plant – quarterly results Quarterly - 1 Jan 2021 to 31 Mar 2021 Characteristics Unit of ADWG No. of Min Ave Max % of test complying with measure samples the guideline E. coli orgs/100 mL not detected in 13 <1 <1 <1 100% 100 mL turbidity NTU 5 13 0.08 0.11 0.20 100% true colour HU 15 13 <2 3 3 100% pH pH units between 6.5 - 8.5 13 7.6 7.7 7.8 100% free chlorine mg/L 5 26 <0.04 <0.04 <0.04 100% monochloramine mg/L 3 26 1.54 1.74 1.86 100% fluoride mg/L 1.5* 13 0.95 1.01 1.06 100% total trihalomethanes mg/L 0.25 16 0.074 0.104 0.132 100% acrylamide mg/L 0.0002 1 <0.0002 <0.0002 <0.0002 100% iron mg/L 0.3 13 0.006 0.008 0.010 100% aluminium mg/L 0.2 13 <0.005 0.007 0.037 100% manganese mg/L 0.1 13 0.001 0.005 0.019 100%

* The long-term fluoride performance for each delivery system in this table is based on customer tap data. We target a value of 1 mg/L. The ADWG specifies a guideline value for fluoride of <1.5 mg/L. The NSW Code of Practice for Fluoridation of Public Water Supplies sets a target that each year >95% of all routine fluoride samples (both treated water from WFPs and customer taps) fall within the concentration range of 0.90 to 1.50 mg/L.  True colour is measured at 400 nm wavelength. Abbreviations: ADWG = Australian Drinking Water Guidelines; Ave = average value; E. coli = Escherichia coli; HU = Hazen units; max = maximum value; mg/L = milligrams per litre; min = minimum value; NTU = nephelometric turbidity units; orgs/100 mL = organisms per 100 millilitres; NA=Not Applicable.

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Table 5 Treated water quality characteristics at Prospect Water Filtration Plant – annual results Annual – 1 Apr 2020 to 31 Mar 2021 Characteristics Unit of ADWG No. of Min Ave Max % of test Meets long- measure samples complying term with the performance guideline measure E. coli orgs/100 mL not detected 52 <1 <1 <1 100% Yes in 100 mL turbidity NTU 5 52 0.07 0.11 0.20 100% Yes true colour HU 15 52 <2 <2 3 100% Yes pH pH units between 6.5 52 7.5 7.7 7.8 100% Yes - 8.5 free chlorine mg/L 5 104 <0.04 <0.04 0.14 100% Yes monochloramine mg/L 3 104 1.54 1.75 1.88 100% Yes fluoride mg/L 1.5* 52 0.92 1.00 1.06 100% Yes total trihalomethanes mg/L 0.25 64 0.033 0.089 0.137 100% Yes n-nitrosodimethylamine mg/L 0.0001 2 <0.00001 <0.00001 0.00001 100% Yes acrylamide mg/L 0.0002 3 <0.0002 <0.0002 <0.0002 100% Yes iron mg/L 0.3 52 <0.005 0.006 0.011 100% Yes aluminium mg/L 0.2 52 <0.005 0.011 0.037 100% Yes manganese mg/L 0.1 52 <0.0005 0.0050 0.0210 100% Yes

* The long-term fluoride performance for each delivery system in this table is based on customer tap data. We target a value of 1 mg/L. The ADWG specifies a guideline value for fluoride of <1.5 mg/L. The NSW Code of Practice for Fluoridation of Public Water Supplies sets a target that each year >95% of all routine fluoride samples (both treated water from WFPs and customer taps) fall within the concentration range of 0.90 to 1.50 mg/L.  True colour is measured at 400 nm wavelength. Abbreviations: ADWG = Australian Drinking Water Guidelines; Ave = average value; E. coli = Escherichia coli; HU = Hazen Units; max = maximum value; mg/L = milligrams per litre; min = minimum value; NTU = nephelometric turbidity units; orgs/100 mL = organisms per 100 millilitres.

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Table 6 Untreated water quality characteristics at Prospect Water Filtration Plant Quarterly - 1 Jan 2021 to 31 Mar 2021 Annual – 1 Apr 2020 to 31 Mar 2021 Characteristics Unit of Raw Water No. of Min Ave Max No. of Min Ave Max measure Supply samples samples Agreement E. coli orgs/100 mL NA 13 <1 3 16 52 <1 2 18 Cryptosporidium oocysts/10 L NA 26 <1 <1 <1 99 <1 <1 <1 Giardia cysts/10 L NA 26 <1 <1 <1 100 <1 <1 <1 turbidity NTU 40 13 1.57 2.28 5.28 52 1.23 3.51 9.25 true colour HU 60 13 10 13 15 52 6 12 21 pH pH units 6.3-7.9 13 7.2 7.3 7.4 52 7.2 7.3 7.6 iron mg/L 3.500 13 0.171 0.225 0.412 52 0.022 0.244 0.412 aluminium mg/L 2.600 13 0.092 0.137 0.294 52 0.031 0.165 0.319 manganese mg/L 1.400 13 0.007 0.016 0.066 52 0.006 0.044 0.234

 True colour is measured at 400 nm wavelength Note: The Raw Water Supply Agreement is an agreement between WaterNSW and Sydney Water about the water quality required Abbreviations: Ave = average value; E. coli = Escherichia coli; HU = Hazen units; max = maximum value; mg/L = milligrams per litre; min = minimum value; NA = not applicable; NTU = nephelometric turbidity units; orgs/100 mL = organisms per 100 millilitres

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What else do we test for? We monitor for all the characteristics found in tables 6-10. If detected, Monitoring for additional chemicals may be done from time to time for results are below the Australian Drinking Water Guidelines value, investigative or other operational purposes but results are not shown wherever a guideline value exists. here for one or more of the following reasons: A range of potential chemical contaminants (metals, organic chemicals • because of the infrequency of monitoring and radionuclides) are monitored in the raw water at the inlet to each • the lack of direct influence on drinking water quality water filtration plant. A few are also monitored in the treated water at • no guideline values exist to compare test results to in order to the plant outlet and at the customer tap. Risk assessments for these assess risk. chemicals take into consideration the physical and chemical properties of the various compounds and usage within the catchment areas. The following tables only show the ADWG health guideline For most of these chemicals, intensive monitoring was initially carried value, the analytical limit of detection, and the frequency of out to establish if they were likely to be present in the supply. This analysis for each chemical. Results are not shown because historical data was used along with risk assessments to determine the analysis is infrequent and the majority of these chemicals are range of potential contaminants and the frequency of analysis for the only rarely detected and at very low levels. current monitoring program. Some chemicals are measured every five years, just to check they are still not present in the water. .

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Table 7 Prospect South Delivery System – other characteristics Characteristic Analyte name ADWG Health/Aesthetic Detection Monitoring Most recent result complies with Guideline Value (mg/L) limit (mg/L) frequency* Australian Drinking Water Guideline Value Inorganic cyanogen chloride 0.08 0.004 2019-20, 1 sample Yes chemicals per delivery system chloride 250 0.10 2016-17, 2 samples Yes per delivery system sodium 180 0.05 2016-17, 2 samples Yes per delivery system hydrogen sulfide 0.05 0.002 2018-19, 2 samples Yes per delivery system Organic benzo-(a)-pyrene 0.00001 0.00001 2016-17, 2 samples Yes chemicals per delivery system di(2-ethylhexly) 0.01 0.01 2017-18, 1 sample Yes phthalate (DEHP) per delivery system toluene 0.8 0.0003 2018-19, 1 sample Yes per delivery system xylene 0.6 0.0004 2017-18, 1 sample Yes per delivery system Chloroacetic chloroacetic acid 0.15 0.001 2018-19, 1 sample Yes acids per delivery system dichloroacetic acid 0.1 0.001 Yes trichloroacetic acid 0.1 0.001 Yes chlorophenols 2-chlorophenol 0.3 0.0001 2018-19, 1 sample Yes per delivery system 2,4-dichlorophenol 0.2 0.0001 Yes 2,4,6-trichlorophenol 0.02 0.0001 Yes

mg/L = milligrams per litre * Monitored on a five-yearly rotational basis – year indicates most recent test performed

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Table 8 Treated water at Prospect Water Filtration Plant – other characteristics Characteristic Analyte name ADWG Health Detection limit Monitoring frequency – Most recent result complies with Guideline Value (mg/L) Prospect Water Filtration Australian Drinking Water Guideline (mg/L) Plant Value

Inorganic antimony 0.003 0.0003 NA1 Yes chemicals cadmium 0.002 0.0001 NA1 Yes copper 2 0.0005 NA1 Yes chromium (as 0.05 0.0002 NA1 Yes Cr(VI)) cyanide 0.08 0.005 NA1 Yes lead 0.01 0.0001 NA1 Yes nickel 0.02 0.0002 NA1 Yes sulfate 500 0.10 quarterly Yes Organic acrylamide 0.0002 0.0002 5-yearly2 Yes chemicals carbon 0.003 0.0003 5-yearly3 Yes tetrachloride toluene 0.8 0.0003 NA4 Yes xylene 0.6 0.0004 NA4 Yes NA = Not Applicable; mg/L = milligrams per litre; ADWG = Australian Drinking Water Guidelines 1 Monitored monthly/quarterly in the customer supply systems rather than in the treated water from the WFP. 2 Monitored on a 5-year rotational basis. Last sampled in 2015-16, sampled in 2020-21, 1 sample for each WFP in each quarter. 3 Monitored on a 5-year rotational basis. Last sampled for each WFP in each quarter during 2016-17. 4 Monitored on a 5-year rotational basis in the customer supply system rather than in the treated water from the WFP.

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Table 9 Untreated water– other characteristics Characteristic Analyte name ADWG Health Guideline Detection limit Monitoring frequency – Prospect Water Value (mg/L) (mg/L) Filtration Plant Inorganic antimony 0.003 0.0003 NA chemicals arsenic 0.01 0.0002 quarterly barium 2 0.0005 quarterly boron 4 0.02 quarterly cadmium 0.002 0.0001 NA iodide 0.5 0.005 yearly mercury 0.001 0.00001 quarterly molybdenum 0.05 0.0001 quarterly selenium 0.01 0.0002 quarterly silver 0.1 0.0001 yearly Organic acrylamide 0.0002 0.0002 NA chemicals benzene 0.001 0.0003 monthly1 1,2-dichlorobenzene 1.5 0.0003 NA 1,4-dichlorobenzene 0.04 0.0005 NA 1,2-dichloroethane 0.003 0.0003 monthly1 1,1-dichloroethene 0.03 0.0003 NA 1,2-dichloroethene 0.06 0.0003 monthly1 dichloromethane (methylene 0.004 0.0003 NA chloride) ethylbenzene 0.3 0.0003 NA ethylenediamine tetraacetic acid 0.25 0.02 NA (EDTA)

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Characteristic Analyte name ADWG Health Guideline Detection limit Monitoring frequency – Prospect Water Value (mg/L) (mg/L) Filtration Plant hexachlorobutadiene 0.0007 0.0003 monthly1 nitrilotriacetic acid (NTA) 0.2 0.02 NA styrene (vinylbenzene) 0.003 0.0004 NA trichlorobenzenes (total) 0.03 0.0003 NA vinyl chloride 0.0003 0.0003 monthly1 xylene 0.6 0.0004 NA NA = Not Applicable; mg/L = milligrams per litre; ADWG = Australian Drinking Water Guidelines 1 Collected monthly but sampling frequency may be reviewed.

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Table 10 Untreated water – pesticides and herbicides Characteristic Analyte name ADWG Health Detection limit (mg/L) Monitoring frequency – Prospect Water Filtration Plant Guideline Value (mg/L)

Pesticides / aldrin 0.0003 0.00001 NA Herbicides amitrole 0.009 0.001 yearly1 atrazine 0.02 0.000025 yearly1 chlordane 0.002 0.00001 NA chlorpyrifos 0.01 0.001 monthly 2,4-D 0.03 0.0001 monthly DDT 0.009 0.00001 NA diazinon 0.004 0.000025 monthly dicamba 0.1 0.0001 NA dieldrin 0.0003 0.00001 NA dimethoate 0.007 0.000025 NA diquat 0.007 0.0001 yearly1 diuron 0.02 0.01 yearly1 endosulfan 0.02 0.00001 NA glyphosate 1 0.005 monthly heptachlor 0.0003 0.00001 yearly1 hexazinone 0.4 0.002 yearly1 lindane 0.01 0.00001 NA methoxychlor 0.3 0.000002 NA metsulfuron-methyl 0.04 0.0001 NA

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Characteristic Analyte name ADWG Health Detection limit (mg/L) Monitoring frequency – Prospect Water Filtration Plant Guideline Value (mg/L)

molinate 0.004 0.000025 NA paraquat 0.02 0.0005 NA 2,4,5-T 0.1 0.0001 yearly1 triclopyr 0.02 0.0001 monthly

NA = Not Applicable; mg/L = milligrams per litre; ADWG = Australian Drinking Water Guidelines 1 Additional samples collected following heavy rain

Table 11 Untreated water– radionuclides Characteristic Analyte name ADWG Health Guideline Value Detection limit Monitoring frequency – Prospect Water Filtration (Bq/L) (Bq/L) Plant

Radiological gross alpha NA1 0.02 yearly gross beta NA1 0.07 yearly total 0.5 0.02 NA radionuclides

NA = Not Applicable. ADWG = Australian Drinking Water Guidelines 1 The sum of gross alpha and gross beta (total radionuclides) should not exceed 0.5 Bq/L (becquerels per litre).

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Water in the catchments We report some information about water quality in WaterNSW’s For more information about quantities of water catchments. Water in your area is sourced from Lake Burragorang in the catchment areas, please visit the at Warragamba Dam, Prospect Lake, and the Upper Canal (which WaterNSW website. conveys water from Nepean and Avon Dams.

Information about untreated water in these catchments is provided below.

Table 12 Lake Burragorang, 500 metres upstream of the dam wall, quarterly results Quarterly Results – 1 Jan 2021 to 31 Mar 2021 Characteristics Unit of measure WaterNSW No. of Min Ave Max Reference levels* samples Microbiological E. coli orgs/100 mL NA 69 <1 1 12 Cryptosporidium oocysts/10 L NA 3 <1 <1 <1 Giardia cysts/10 L NA 3 <1 <1 <1 Physical / chemical turbidity NTU NA 13 0.40 2.40 15.00 true colour HU NA 69 10 19 34 chlorophyll - a μg/L 2-10 47 0.7 5.0 10.0 iron mg/L <1 69 0.010 0.273 2.160 aluminium mg/L <0.1 69 <0.010 0.225 2.010 manganese mg/L 0.5 69 0.001 0.032 0.409

 True colour is measured at 400 nm wavelength * Australian Drinking Water Guidelines for fresh and Marine Waters, ANZECC & ARMCANZ, 2000. Abbreviations: Ave = average value; E. coli = Escherichia coli; HU = Hazen Units; max = maximum value; mg/L = milligrams per litre; min = minimum value; NTU = nephelometric turbidity units; orgs/100 mL = organisms per 100 millilitres; cysts/10 L = Giardia cysts per 10 litres; oocysts/10 L = Cryptosporidium oocysts per 10 litres; NA=Not Applicable.

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Table 13 Lake Burragorang, 500 metres upstream of the dam wall, annual results Annual Results – 1 Apr 2020 to 31 Mar 2021 Characteristics Unit of measure WaterNSW No. of Min Ave Max Reference levels* samples Microbiological E. coli orgs/100 mL NA 269 <1 1 17 Cryptosporidium oocysts/10 L NA 32 <1 1 11 Giardia cysts/10 L NA 32 <1 <1 3 Physical / chemical turbidity NTU NA 67 0.40 3.90 15.00 true colour HU NA 179 7 22 44 chlorophyll - a μg/L 2-10 178 0.4 5.0 25.5 iron mg/L <1 271 0.010 0.295 2.160 aluminium mg/L <0.1 269 <0.010 0.259 2.030 manganese mg/L 0.5 271 0.001 0.048 0.826

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Table 9 Upper Canal, quarterly results Quarterly Results 1 Jan 2020 to 31 Mar 2021 Characteristics Unit of measure WaterNSW No. of Min Ave Max Reference levels* samples Microbiological E. coli orgs/100 mL NA 7 <1 96 200 Cryptosporidium oocysts/10 L NA 0 NA NA NA Giardia cysts/10 L NA 0 NA NA NA Physical / chemical turbidity NTU NA 7 0.50 1.36 3.16 true colour HU NA 7 12 15 24 chlorophyll - a μg/L NA 7 0.3 2.1 3.9 iron mg/L <1 7 0.300 0.556 1.360 aluminium mg/L <0.1 7 0.040 0.096 0.240 manganese mg/L NA 7 0.007 0.026 0.104

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Table 15 Upper Canal, annual results Annual Results – 1 Apr 2020 to 31 Mar 2021 Characteristics Unit of measure WaterNSW No. of Min Ave Max Reference levels* samples Microbiological E. coli orgs/100 mL NA 22 <1 41 200 Cryptosporidium oocysts/10 L NA 0 NA NA NA Giardia cysts/10 L NA 0 NA NA NA Physical / chemical turbidity NTU NA 22 0.50 2.31 6.51 true colour HU NA 17 10 14 24 chlorophyll - a μg/L NA 22 0.2 1.3 3.9 iron mg/L <1 21 0.300 0.493 1.360 aluminium mg/L <0.1 21 0.040 0.133 0.280 manganese mg/L NA 22 0.007 0.018 0.104

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Table 16 Prospect Lake, quarterly results Quarterly Results – 1 Jan 2021 to 31 Mar 2021 Characteristics Unit of measure WaterNSW No. of Min Ave Max Reference levels* samples Microbiological E. coli orgs/100 mL NA 4 <1 3 8 Cryptosporidium oocysts/10 L NA 24 <1 <1 2 Giardia cysts/10 L NA 24 <1 <1 3 Physical / chemical turbidity NTU NA 207 0.83 1.76 9.69 true colour HU NA 4 4 4 5 chlorophyll - a μg/L 2-10 6 7.8 11.4 15.1 iron mg/L <1 4 0.050 0.073 0.090 aluminium mg/L <0.1 4 0.030 0.038 0.050 manganese mg/L 0.5 4 0.020 0.026 0.035

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Table 17 Prospect Lake, annual results Annual Results – 1 Apr 2020 to 31 Mar 2021 Characteristics Unit of measure WaterNSW No. of Min Ave Max Reference levels* samples Microbiological E. coli orgs/100 mL NA 12 <1 3 10 Cryptosporidium oocysts/10 L NA 100 <1 <1 2 Giardia cysts/10 L NA 99 <1 <1 9 Physical / chemical turbidity NTU NA 807 0.83 1.86 9.69 true colour HU NA 8 4 5 6 chlorophyll - a μg/L 2-10 18 5.1 9.8 15.1 iron mg/L <1 12 0.050 0.077 0.120 aluminium mg/L <0.1 12 0.030 0.049 0.090 manganese mg/L 0.5 12 0.009 0.017 0.035

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to characterise the full pathogen reduction capability. Since we have Review of drinking water literature existing schemes and already supplying to customers, it would be very difficult to perform validation without impacting our production, increasing the risk of treatment failure.

To solve this issue, we have developed the detailed verification Every quarter, we review a topic from the latest monitoring approach. Under the approach, monitoring of microorganism water quality research from around the world. reduction is performed in situ and without interruption to the water treatment process. It is currently used across all our recycled water schemes. The program assesses the removal of selected microorganisms that are present at high numbers in the untreated source water. These selected microorganism surrogates represent the Detailed verification monitoring of water treatment for quality three main groups of pathogens (bacteria, protozoa and viruses). The assurance: Lessons from the water recycling experience reduction of these microorganisms mathematically relates to the reduction of pathogens. As seen in this report, we focus strongly on assuring the safety of your drinking water. You might not know that we also manage fourteen water When the measured microorganisms fall to non-measurable levels, we recycling schemes. The recycled supplies are currently used for non- use the scientific literature and expert guidance to understand the levels drinking purposes, including the irrigation, industry use, river health of reduction achievable under the conditions of our water treatment improvement, and through a separate dedicated ‘purple pipe’ area in processes. This applies particularly towards the end of the chain of north-west Sydney. treatment processes, as the microorganisms often have been reduced below levels that can be measured. For example, to predict virus Advancements in water recycling approaches can similarly improve our reduction when using chlorine to disinfect recycled water, we have protection of the drinking water supply. One example is the approach referred to an authoritative publication based on peer-reviewed science1 we use to measure the elimination of potentially harmful pathogens by that considers the concentration of chlorine, the length of time of water treatment processes. Effective management of pathogens, in line chlorine treatment, as well as the turbidity, temperature and pH of the with the Australian Guidelines for Water Recycling (AGWR), is critical water. The relationships are well established and well understood. The for the protection of public health and the environment. approach has been developed in consultation with NSW Health.

Assessing the effectiveness of water treatment: Detailed Through the detailed verification program, we have assessed the verification monitoring effectiveness of our water recycling treatment processes to reduce pathogens. This can be compared to guideline requirements. If There are varying approaches to understand the capability of water necessary, we can add further additional safeguards such as more treatment processes to eliminate pathogens. One such way is treatment or avoiding people coming in contact with the recycled water validation, performed by either by the manufacturer or the water utility. if there is insufficient elimination of pathogens. This means we are Validation determines the pathogen reduction capacity of each of the confident in our supply of recycled water safely to our customers. As treatment processes in relation to measurable operating conditions. well as developing a more detailed understanding of the removals of This includes stressing (potentially to near failure) the process artificially key microorganisms through our treatment processes, we have

Quarterly Drinking Water Quality Report | Prospect South Delivery System 1 January 2021 to 31 March 2021 26 improved our in-house laboratory and field sampling expertise of when, recommend assuring ongoing pathogen reduction by continuously where and how to monitor for both the appropriate pathogens and measuring either a physical component of the water, such as the surrogates. reduction of particles (turbidity) by filters and the disinfectant dose 1 Guidelines for validating treatment processes for pathogen reduction: Supporting Class A added to the water. Validating that a new facility can meet the pathogen recycled water schemes in Victoria (2013). Victorian Department of Health. reduction targets in advance by challenging it with high levels of

pathogens or surrogates over a range of operating conditions would be impractical and prohibitively expensive. However, it may be possible in Further improvements proposed the future to find suitable representative surrogate microorganisms in We continue to seek emerging knowledge that can further advance this the source waters used for drinking water supplies and to measure their program including through our own research. Soon-to-be Dr Chris reduction during treatment. Doing so as part of the commissioning Owens studied our current Sydney Water detailed verification process and from time to time afterwards would provide further monitoring program as part of his doctoral thesis. He identified that the verification of the effectiveness of our drinking water treatment program could be made more robust by: processes in removing pathogens. In other words, based on our experience in recycling water, we may be able to apply the principal of 1. Confirming the relationships of each of the measured detailed verification to drinking water to increase confidence in the microorganisms to the corresponding pathogen group in the control of risks from potentially harmful microorganisms. untreated source water. 2. Improving methods to understand the reduction of the representative microorganisms, including a better understanding of the range of results obtained over the sampling program. 3. Providing more information on the reduction of key pathogens and the corresponding representative microorganisms we measure through the range of treatment processes used to treat water. The research is currently in preparation for publication. Though it focuses on water recycling, it will also provide benefit to the management of drinking water safety.

Potential to further increase the assurance of drinking water quality Over the last two decades there has been considerable effort to match the level of treatment of drinking water to the likely levels of pathogens coming from catchments. The basis for the technologies used in a modern water treatment plant and how they are operated comes from published research and well-documented experience. After building plants based on this knowledge, the drinking water guidelines

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If you have any questions or concerns about your water quality or the information in this report, please get in contact at our website or by calling 13 20 90. sydneywater.com.au

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