🚰
Australian Drinking Water Guidelines
Go to NHMRC's website
  • Australian Drinking Water Guidelines
  • Copyright
  • Table of updates
  • Contents
  • Figures
  • Tables
  • Boxes
  • Introduction
    • Chapter 1: Introduction
      • 1.1 Guiding principles
      • 1.2 About the Guidelines
        • 1.2.1 Scope of the Guidelines
        • 1.2.2 Purpose of the Guidelines
        • 1.2.3 Structure of the Guidelines
      • 1.3 Water quality characteristics
        • 1.3.1 Introduction
        • 1.3.2 Health-based targets
        • 1.3.3 Microbial health-based targets
        • 1.3.4 Physical and chemical guideline values
        • 1.3.5 Radiological screening and reference values
      • 1.4 Community consultation
      • 1.5 Development of the Guidelines
        • 1.5.1 Acknowledgments
      • 1.6 Future revisions of the Guidelines
      • 1.7 References
  • Part 1: Management of Drinking Water Quality
    • Chapter 2: Framework for Management of Drinking Water Quality: overview
      • 2.1 A preventive strategy from catchment to consumer
      • 2.2 Structure of the Framework
      • 2.3 Benefits of the Framework
      • 2.4 The need for multi-agency involvement
      • 2.5 Applying the Framework
      • 2.6 Correlations of the Framework with other systems
    • Chapter 3: Framework for Management of Drinking Water Quality: the twelve elements
      • 3.1 Commitment to drinking water quality management (element 1)
        • 3.1.1 Drinking water quality policy
        • 3.1.2 Regulatory and formal requirements
        • 3.1.3 Engaging stakeholders
      • 3.2 Assessment of the drinking water supply system (element 2)
        • 3.2.1 Water supply system analysis
        • 3.2.2 Assessment of water quality data
        • 3.2.3 Hazard identification and risk assessment
      • 3.3 Preventive measures for drinking water quality management (element 3)
        • 3.3.1 Preventive measures and multiple barriers
        • 3.3.2 Critical control points
      • 3.4 Operational procedures and process control (element 4)
        • 3.4.1 Operational procedures
        • 3.4.2 Operational monitoring
        • 3.4.3 Corrective action
        • 3.4.4 Equipment capability and maintenance
        • 3.4.5 Materials and chemicals
      • 3.5 Verification of drinking water quality (element 5)
        • 3.5.1 Drinking water quality monitoring
        • 3.5.2 Consumer satisfaction
        • 3.5.3 Short-term evaluation of results
        • 3.5.4 Corrective action
      • 3.6 Management of incidents and emergencies (element 6)
        • 3.6.1 Communication
        • 3.6.2 Incident and emergency response protocols
      • 3.7 Employee awareness and training (element 7)
        • 3.7.1 Employee awareness and involvement
        • 3.7.2 Employee training
      • 3.8 Community involvement and awareness (element 8)
        • 3.8.1 Community consultation
        • 3.8.2 Communication
      • 3.9 Research and development (element 9)
        • 3.9.1 Investigative studies and research monitoring
        • 3.9.2 Validation of processes
        • 3.9.3 Design of equipment
      • 3.10 Documentation and reporting (element 10)
        • 3.10.1 Management of documentation and records
        • 3.10.2 Reporting
      • 3.11 Evaluation and audit (element 11)
        • 3.11.1 Long-term evaluation of results
        • 3.11.2 Audit of drinking water quality management
      • 3.12 Review and continual improvement (element 12)
        • 3.12.1 Review by senior executive
        • 3.12.2 Drinking water quality management improvement plan
      • 3.13 References
    • Chapter 4: Framework for the Management of Drinking Water Quality: application to small water supplies
      • 4.1 Introduction
      • 4.2 Applying the Framework
        • 4.2.1 Assessment of the drinking water supply
        • 4.2.2 Preventive measures for drinking water quality management
        • 4.2.3 Implementation of operational procedures and process control
        • 4.2.4 Verification of drinking water quality
      • 4.3 Individual household supplies
      • 4.4 Reference
  • Part 2: Description of Water Quality
    • Chapter 5: Microbial Quality of Drinking Water (Updated 2022)
      • 5.1 Introduction
      • 5.2 Microorganisms in drinking water
      • 5.3 Assessing microbial risk
      • 5.4 Enteric pathogens
        • 5.4.1 Enteric pathogens of concern in drinking water
        • 5.4.2 Contamination of source waters with enteric pathogens
        • 5.4.3 Management of risk from enteric pathogens
      • 5.5 Opportunistic pathogens
      • 5.6 Cyanobacteria
      • 5.7 Nuisance organisms
        • 5.7.1 Organisms causing taste and odour problems
        • 5.7.2 Organisms causing colour problems
        • 5.7.3 Deposits due to iron and manganese bacteria
        • 5.7.4 Corrosion problems due to iron and sulphur bacteria
        • 5.7.5 Problems caused by large numbers of microorganisms
      • 5.8 References
    • Chapter 6: Physical and Chemical Quality of Drinking Water
      • 6.1 Introduction
      • 6.2 Physical quality of drinking water
        • 6.2.1 An overview of physical characteristics
        • 6.2.2 Approach used in derivation of guidelines values for physical characteristics
      • 6.3 Chemical quality of drinking water
        • 6.3.1 Inorganic chemicals
        • 6.3.2 Organic compounds (Revised 2011)
        • 6.3.3 Approach used in derivation of guideline values for chemicals
      • 6.4 Differences between Australian and WHO guideline values
      • 6.5 National and international guideline values (2016)
      • 6.6 References
    • Chapter 7: Radiological Quality of Drinking Water (Updated 2022)
      • 7.1 Introduction
      • 7.2 Sources of radiation in the environment and in drinking water
      • 7.3 Health effects of radiation
      • 7.4 Exposure to radiation
      • 7.5 Units of radioactivity and radiation dose measurement
        • 7.5.1 Units of radioactivity and radiation dose
        • 7.5.2 Converting intake to radiation dose
        • 7.5.3 Average dose of radiation
      • 7.6 Approach for derivation of reference levels and screening values for radionuclides
        • 7.6.1 System for radiation protection
        • 7.6.2 Estimation of the dose from radionuclides in water
        • 7.6.3 Estimation of risk from low-level radiation
        • 7.6.4 Reference levels and screening values for drinking water
        • 7.6.5 Application of reference levels
        • 7.6.6 Remedial measures
      • 7.7 References
    • Chapter 8: Drinking Water Treatment Chemicals (Revised 2006)
      • 8.1 Introduction
      • 8.2 Scope and limit of application of this chapter
      • 8.3 Overview of chemical treatment processes
        • 8.3.1 Control of algae
        • 8.3.2 Coagulation and flocculation
        • 8.3.3 Adsorption
        • 8.3.4 Softening
        • 8.3.5 Oxidation
        • 8.3.6 Disinfection
        • 8.3.7 Adjustment of pH
        • 8.3.8 Addition of buffering capacity
        • 8.3.9 Corrosion inhibition
      • 8.4 Public health measures
        • 8.4.1 Fluoridation
      • 8.5 Assessment of Chemicals acceptable for use in drinking water treatment (revised 2016)
        • 8.5.1 Chemicals assessed prior to 2004
        • 8.5.2 New water treatment chemicals
      • 8.6 Quality assurance for drinking water treatment chemicals
        • 8.6.1 Risks associated with drinking water chemicals
        • 8.6.2 Managing risks
        • 8.6.3 Specifications for the supply of drinking water treatment chemicals
      • 8.7 Monitoring and analytical requirements
      • 8.8 Contaminants in drinking water treatment chemicals
      • 8.9 Useful contacts
      • 8.10 References
  • Part 3: Monitoring
    • Chapter 9: Overview of monitoring (Revised 2021)
      • 9.1 Introduction
      • 9.2 Monitoring overview
        • 9.2.1 Monitoring priorities
        • 9.2.2 Principles of monitoring frequency
        • 9.2.3 Catchment-to-consumer monitoring
      • 9.3 Developing a monitoring program
      • 9.4 Operational monitoring
        • 9.4.1 Operational characteristics
        • 9.4.2 Target criteria
        • 9.4.3 Critical limits at critical control points
        • 9.4.4 Corrective action
        • 9.4.5 Operational monitoring frequency
        • 9.4.6 Chlorination as a critical control point: an example
      • 9.5 Verification of drinking water quality
        • 9.5.1 Monitoring consumer satisfaction
        • 9.5.2 Drinking water quality monitoring
      • 9.6 Water quality issues beyond the point of supply
      • 9.7 Investigative studies and research monitoring
      • 9.8 Validation of barrier performance
      • 9.9 Incident and emergency response monitoring
      • 9.10 Reliability of monitoring data
        • 9.10.1 Sample integrity
        • 9.10.2 Methods
        • 9.10.3 Detection limits
        • 9.10.4 Measurement uncertainty
        • 9.10.5 Field testing
      • 9.11 Monitoring advice for small, remote or community-managed water supplies
      • 9.12 Assessing the significance of short-term exceedances of health-based guideline values
      • 9.13 References
    • Chapter 10: Monitoring for specific characteristics in drinking water (Updated 2022)
      • 10.1 Introduction
      • 10.2 Assessing safety: short-term evaluation of monitoring
        • 10.2.1 Short-term evaluation of operational monitoring
        • 10.2.2 Short-term evaluation of drinking water quality monitoring
      • 10.3 Assessing performance: long-term evaluation of monitoring
        • 10.3.1 Long-term evaluation of microbial performance
        • 10.3.2 Long-term evaluation of health-based chemical performance
        • 10.3.3 Long-term evaluation of aesthetic performance
        • 10.3.4 Long-term evaluation of consumer satisfaction
        • 10.3.5 Improvement plan
        • 10.3.6 Performance reporting
        • 10.3.7 Summary of guideline values for microbial, chemical and physical characteristics
        • 10.3.8 Summary of reference levels and screening values for radiological characteristics
      • 10.4 Reference
  • Part 4: Information sheets
    • 1. Disinfection
      • 1.1: Introduction to water treatment
      • 1.2: Overview of disinfection
      • 1.3: Disinfection with chlorine
      • 1.4: Chloramines
      • 1.5: Disinfection with chlorine dioxide
      • 1.6: Disinfection with ozone
      • 1.7: Disinfection with ultraviolet light
      • 1.8: Other disinfectants
    • 2. Sampling
      • 2.1: Sampling Information – handling requirements and preservation
      • 2.2: Radiological monitoring and assessment of performance (updated 2022)
    • 3. Statistics
      • 3.1: Statistics – Visualising data
      • 3.2: Statistics – Assessing data
      • 3.3: Statistics – Statistical principles
      • 3.4: Statistics – Control charts and trends
      • 3.5: Number of samples required
      • 3.6: Guidance for issuing and lifting boil water advisories
      • Attachments
  • Part 5: Fact sheets
    • Microorganisms
      • Microbial indicators
        • Bacteroides
        • Coliphages
        • Clostridium perfringens
        • Escherichia coli
        • Heterotrophic plate counts
        • Intestinal enterococci
        • Thermotolerant coliforms
        • Total coliforms
      • Bacteria
        • Aeromonas
        • Burkholderia pseudomallei
        • Campylobacter
        • Escherichia coli (E. coli) (pathogenic)
        • Helicobacter pylori
        • Klebsiella
        • Legionella
        • Mycobacterium
        • Pseudomonas aeruginosa
        • Salmonella
        • Shigella
        • Vibrio
        • Yersinia
      • Protozoa
        • Acanthamoeba
        • Blastocystis
        • Cryptosporidium
        • Cyclospora
        • Giardia
        • Naegleria fowleri
      • Cyanobacteria and their toxins
        • Cyanobacteria and their toxins
        • Cylindrospermopsin
        • Microcystins
        • Nodularin
        • Saxitoxins
      • Viruses
        • Adenovirus
        • Enterovirus
        • Hepatitis viruses
        • Norovirus
        • Rotavirus
    • Physical and chemical characteristics
      • Acephate
      • Acrylamide
      • Aldicarb
      • Aldrin and Dieldrin
      • Aluminium
      • Ametryn
      • Amitraz
      • Amitrole
      • Ammonia
      • Antimony
      • Arsenic
      • Asbestos
      • Asulam
      • Atrazine
      • Azinphos-methyl
      • Barium
      • Benomyl
      • Bentazone
      • Benzene
      • Beryllium
      • Bioresmethrin
      • Boron
      • Bromacil
      • Bromate
      • Bromoxynil
      • Cadmium
      • Captan
      • Carbaryl
      • Carbendazim/Thiophanate-methyl
      • Carbofuran
      • Carbon tetrachloride
      • Carboxin
      • Carfentrazone-ethyl
      • Chloral hydrate (Trichloroacetaldehyde)
      • Chlorantraniliprole
      • Chlordane
      • Chlorfenvinphos
      • Chloride
      • Chlorinated furanones
      • Chlorine
      • Chlorine dioxide, Chlorite, Chlorate
      • Chloroacetic acids: chloroacetic acid, dichloroacetic acid (DCA), trichloroacetic acid (TCA)
      • Chlorobenzene
      • Chloroketones
      • Chlorophenols
      • Chloropicrin
      • Chlorothalonil
      • Chlorpyrifos
      • Chlorsulfuron
      • Chromium
      • Clopyralid
      • Colour (True)
      • Copper
      • Cyanide
      • Cyanogen chloride
      • Cyfluthrin, Beta-cyfluthrin
      • Cypermethrin isomers
      • Cyprodinil
      • 2,4-D [(2,4-Dichlorophenoxy) acetic acid]
      • DDT (1,1,1-trichloro-di-(4-chlorophenyl) ethane)
      • Deltamethrin
      • Diazinon
      • Dicamba
      • Dichlorobenzenes
      • Dichloroethanes: 1,1-dichloroethane, 1,2-dichloroethane
      • Dichloroethenes: 1,1-dichloroethene (1,1-DCE), 1,2-dichloroethene (1,2-DCE)
      • Dichloromethane (methylene chloride)
      • 1,3-Dichloropropene
      • Dichlorprop/Dichlorprop-P
      • Dichlorvos
      • Diclofop-methyl
      • Dicofol
      • Diflubenzuron
      • Dimethoate
      • Diquat (ion), Diquat dibromide
      • Dissolved oxygen
      • Disulfoton
      • Diuron
      • 2,2-DPA
      • Endosulfan
      • Endothal
      • Epichlorohydrin
      • EPTC
      • Esfenvalerate
      • Ethion
      • Ethoprophos
      • Ethylbenzene
      • Ethylenediamine tetraacetic acid (EDTA)
      • Etridiazole
      • Fenamiphos
      • Fenarimol
      • Fenchlorphos
      • Fenitrothion
      • Fenthion
      • Fenvalerate
      • Fipronil
      • Flamprop-methyl
      • Fluometuron
      • Fluoride
      • Flupropanate
      • Formaldehyde
      • Glyphosate
      • Haloacetonitriles
      • Haloxyfop
      • Hardness (as calcium carbonate)
      • Heptachlor and heptachlor epoxide
      • Hexachlorobutadiene
      • Hexazinone
      • Hydrogen sulfide, Sulfide
      • Imazapyr
      • Iodine, Iodide
      • Iprodione
      • Iron
      • Lanthanum
      • Lead
      • Lindane
      • Maldison (Malathion)
      • Mancozeb
      • Manganese
      • MCPA
      • Mercury
      • Metaldehyde
      • Metham
      • Methidathion
      • Methiocarb
      • Methomyl
      • Methyl bromide
      • Metiram
      • Metolachlor/s-Metolachlor
      • Metribuzin
      • Metsulfuron-methyl
      • Mevinphos
      • Molinate
      • Molybdenum
      • Monochloramine
      • Naphthalophos
      • Napropamide
      • Nicarbazin
      • Nickel
      • Nitrate and nitrite
      • Nitrilotriacetic acid (NTA)
      • N-Nitrosodimethylamine (NDMA)
      • Norflurazon
      • Omethoate
      • Organotins: dialkyltins, tributyltin oxide
      • Oryzalin
      • Oxamyl
      • Paraquat
      • Parathion
      • Parathion-methyl
      • Pebulate
      • Pendimethalin
      • Pentachlorophenol
      • Per-fluoroalkyl and poly-fluoroalkyl substances (PFAS)
      • Permethrin
      • pH
      • Picloram
      • Piperonyl butoxide
      • Pirimicarb
      • Pirimiphos methyl
      • Plasticisers
      • Polihexanide
      • Polycyclic aromatic hydrocarbons (PAHs)
      • Profenofos
      • Promecarb
      • Propachlor
      • Propanil
      • Propargite
      • Propazine
      • Propiconazole
      • Propyzamide
      • Pyrasulfotole
      • Pyrazophos
      • Pyroxsulam
      • Quintozene
      • Radionuclides, Specific Alpha and Beta Emitting
      • Radium (radium-226 and radium-228)
      • Radon-222
      • Selenium
      • Silica
      • Silver
      • Simazine
      • Sodium
      • Spirotetramat
      • Styrene (vinylbenzene)
      • Sulfate
      • Sulprofos
      • Taste and Odour
      • Temephos
      • Temperature
      • Terbacil
      • Terbufos
      • Terbuthylazine
      • Terbutryn
      • Tetrachloroethene
      • Thiobencarb
      • Thiometon
      • Thiram
      • Tin
      • Toltrazuril
      • Toluene
      • Total dissolved solids
      • Triadimefon
      • Trichlorfon
      • Trichlorobenzenes
      • 1,1,1-Trichloroethane
      • Trichloroethylene (TCE)
      • Triclopyr
      • Trifluralin
      • Trihalomethanes (THMs)
      • Turbidity
      • Uranium
      • Vernolate
      • Vinyl chloride
      • Xylenes
      • Zinc
    • Drinking water treatment chemicals
      • Aluminium chlorohydrate
      • Aluminium sulfate (alum)
      • Ammonia
      • Ammonium sulfate
      • Calcium hydroxide
      • Calcium hypochlorite
      • Calcium oxide
      • Carbon, granulated activated
      • Carbon, powdered activated
      • Chlorine
      • Copper sulfate
      • Ferric chloride
      • Ferric sulfate
      • Hydrochloric acid
      • Hydrofluorosilicic acid
      • Hydrogen peroxide
      • Hydroxylated ferric sulfate
      • Ozone
      • Polyacrylamide
      • Polyaluminium chloride
      • Polyaluminium silica sulfates
      • Polydiallyldimethylammonium chloride
      • Potassium permanganate
      • Sodium aluminate
      • Sodium bicarbonate
      • Sodium carbonate
      • Sodium fluoride
      • Sodium fluorosilicate
      • Sodium hexametaphosphate
      • Sodium hydroxide
      • Sodium hypochlorite
      • Sodium silicate
      • Sodium tripolyphosphate
      • Sulfuric acid
      • Zinc orthophosphate
  • Appendices
    • Appendix 1: Additional guidance
      • A1.1 Introduction
      • A1.2 Water supply system analysis
      • A1.3 Assessment of water quality data
      • A1.4 Hazard identification
      • A1.5 Risk assessment
      • A1.6 Preventive measures and multiple barriers
      • A1.7 Critical control points
      • A1.8 Chlorination as an example of a critical control point
      • A1.9 References
    • Appendix 2: Further sources of information on drinking water quality management
      • A2.1 Drinking water quality management - general
      • A2.2 Catchment management and source water protection
      • A2.3 Groundwater protection
      • A2.4 Risk assessment and management
      • A2.5 System analysis and management process control and optimisation
      • A2.6 Monitoring and verification
      • A2.7 Materials and chemicals
      • A2.8 Incident and emergency management
      • A2.9 Employee training and awareness
      • A2.10 Research and development
      • A2.11 Documentation and reporting
      • A2.12 Community consultation and communication
      • A2.13 Hazard analysis and critical control point (HACCP)
      • A2.14 Quality management continuous improvement
      • A2.15 Reference web sites
    • Appendix 3: Derivation of microbial treatment targets for enteric pathogens
      • A3.1 Introduction to Quantitative Microbial Risk Assessment (QMRA)
      • A3.2 Adopting the QMRA approach in the Guidelines
      • A3.3 QMRA framework for the calculation of log₁₀ reduction values (LRVs)
      • A3.4 Defining the health outcome target
      • A3.5 Selection of reference pathogens
      • A3.6 Level of reference pathogen contamination in Australian source waters
      • A3.7 Consumption volume of unheated (unboiled) water per person per day
      • A3.8 Dose response relationships
      • A3.9 Disability Adjusted Life Years (DALY) burden per case
      • A3.10 Calculation of LRVs using the QMRA framework
      • A3.11 Interpretation of calculated LRVs for practical treatment guidance
      • A3.12 Understanding log₁₀ reductions
      • A3.13 References
  • Glossary
Powered by GitBook
LogoLogo

Australian Drinking Water Guidelines 6 2011, v3.9

  • Go back to NHMRC website
On this page
  • Table A1.2 Examples of sources and potential hazardsᵃ
  • Table A1.3 Examples of hazardous events and their potential sources
  1. Appendices
  2. Appendix 1: Additional guidance

A1.4 Hazard identification

Adoption of a risk-based approach that includes the identification of hazards from catchment to consumer and the assessment of the potential impact on drinking water quality and human health (i.e. risk) is essential to effective system management. Hazard identification and risk assessment are useful for understanding the vulnerability of a drinking water supply and planning effective risk management strategies to assure drinking water quality and safety.

The purpose of this element is to identify and document all potential hazards and the hazardous events and sources that might give rise to the presence of these hazards.

Summary of actions

  • Define the approach and methodology to be used for hazard identification. Devise an evaluation team with appropriate representatives.

  • Review hazardous agents in drinking water and ensure that their link to public health is understood (see Section V — Fact Sheets).

  • Identify and document hazards, sources and hazardous events for each component of the water supply system (see Tables A1.2 and A1.3).

  • Periodically review and update the hazard identification to incorporate any new hazards.

A structured approach is important to ensure that significant issues are not overlooked and that areas of greatest risk are identified. There is no single right way to perform these activities; however, the process should involve a structured and comprehensive evaluation of the water supply system.

For each component of the water supply system, all hazards and hazardous events and sources that might affect drinking water quality and safety (what can happen and how) should be identified and documented. Table A1.2 provides examples of various pollution sources and the potential hazards they produce.

All potential hazards, hazardous events and sources should be included in the assessment, regardless of whether or not they are under the direct control of the drinking water supplier. Continuous, intermittent or seasonal pollution patterns should also be considered as well as extreme and infrequent events such as droughts or floods. Table A1.3 provides examples of potential sources and hazardous events, from catchment to consumer, to be considered.

Table A1.2 Examples of sources and potential hazardsᵃ

Potential sources
Potential hazard

Septic tanks

Pathogensᵇ, nitrates/nitrites

Sewage treatment plants

Pathogens, nutrients

Animal husbandry

Pathogens, nutrients, turbidity, colour

Horticulture

Pesticides, fertiliser nutrients, turbidity, colour

Rural stormwater

Pathogens, turbidity, colour

Forestry

Pesticides, turbidity, colour

Industry

Heavy metals, organic chemicals including halogenated organics; specific industries can be associated with specific types of contaminants (e.g. arsenic and copper associated with wood preserving, cadmium and chromium with electroplating and chromium with leather tanning)

Mining

Acid mine wastes from pyrites tailings can release and transport metals such as aluminium, iron and manganese; other naturally occurring metals such as cadmium and copper can also be leached; arsenic can be associated with old goldfield areas

Urban stormwater

Lead and zinc from roads, turbidity, colour, petrol/oil products, microorganisms from pets (lower range of pathogens than from humans or livestock waste)

Stormwater/sewer overflows

Pathogens, nutrients, turbidity, colour

ᵃ Human and animal waste represent the largest sources of potential hazards in drinking water. Both can include high numbers of enteric pathogens and large amounts of nutrients. Due to the scale of primary production in Australia, the total amount of livestock waste would greatly exceed the amount of human waste.

ᵇ The potential range of pathogens present will vary according to the type of waste involved. Many enteric pathogens, and in particular viruses and protozoa, infect only one species. In general, human enteric viruses are only carried and excreted by humans. Human infectious Cryptosporidium parvum can be carried by humans and livestock, but the current state of knowledge suggests that the species of Cryptosporidium that infect birds do not infect humans.

Table A1.3 Examples of hazardous events and their potential sources

Catchments and groundwater systems
Catchments and groundwater systems (continued)
  • Rapid variations in raw water quality

  • Sewage and septic system discharges

  • Industrial discharges

  • Chemical use in catchment areas (e.g. use of fertilisers and agricultural pesticides)

  • Major spills and accidental spillage

  • Public roads

  • Human access (recreational activity)

  • Wildlife (native and feral)

  • Unrestricted livestock

  • Inadequate buffer zones

  • Surrounding land use (e.g. animal husbandry, agriculture, forestry, industrial area, waste disposal, mining)

  • Changes in surrounding land use

  • Poorly vegetated riparian zones, failure of sediment traps and soil erosion

  • Stormwater flows and discharges

  • Existing or historical waste-disposal or mining sites/ contaminated sites and hazardous wastes

  • Unconfined and shallow aquifers

  • Groundwater under direct influence of surface water

  • Inadequate well-head protection and unhygienic practices

  • Uncased or inadequately cased bores

  • Saline intrusion of coastal aquifers

  • Contaminated aquifers

  • Climatic and seasonal variations (e.g. heavy rainfalls, droughts)

  • Bushfires, natural disasters, sabotage

Storage reservoirs and intakes
Storage reservoirs and intakes (continued)
  • Open reservoirs and aqueducts, uncovered storages

  • Human access/absence of exclusion areas around shorelines

  • Animal access including birds and vermin

  • Short-circuiting of reservoir

  • Depletion of reservoir storage

  • No selective withdrawal

  • No alternative water sources

  • Unsuitable intake location

  • Cyanobacterial blooms

  • Stratification

  • Soil erosion

  • Inadequate buffer zones and vegetation

  • Climatic and seasonal variations (e.g. heavy rainfalls, droughts)

  • Public roads / accidental spillage

  • Failure of alarms and monitoring equipment

  • Bushfires and natural disasters

  • Sabotage

Treatment systems
Treatment systems (continued)
  • Significant flow variations through water treatment system

  • Incapable equipment or unit processes

  • Inadequate backup

  • Inappropriate treatment processes

  • Process control incapability or operational inflexibility

  • Use of unapproved or contaminated water treatment chemicals and materials

  • Chemical dosing failures

  • Inadequate mixing

  • Failure of dosing equipment

  • Inadequate filter operation and backwash recycling

  • Ineffective disinfection

  • Equipment malfunctions

  • Poor reliability of processes

  • Failure of alarms and monitoring equipment

  • Power failures

  • Sabotage and natural disasters

  • Formation of disinfection byproducts

Service reservoirs and distribution systems
Service reservoirs and distribution systems (continued)
  • Open reservoirs and aqueducts / uncovered storages and unprotected pipe system

  • Human access, absence of exclusion areas around shorelines

  • Animal access including birds and vermin

  • Short-circuiting of reservoir, stagnation zones

  • Buildup of sediments and slimes

  • Inappropriate materials and coatings or material failure

  • Aged pipes, infrastructure

  • Corrosion of reservoirs and pipe system

  • Mixing of different source waters

  • Infiltration and ingress of contamination from cross-connections, backflow (soil and groundwater)

  • Biofilms, sloughing and resuspension, regrowth

  • Pipe bursts or leaks

  • Inadequate repair and maintenance, inadequate system flushing and reservoir cleaning

  • Commissioning new mains

  • Inadequate disinfection after construction, repairs

  • Flow variability, inadequate pressures

  • Treatment dosing failure

  • Inadequate maintenance of chlorine residual

  • Formation of disinfection byproducts

  • Failure of alarms and monitoring equipment

  • Sabotage and natural disasters

Consumers
Consumers (continued)
  • Potential consumer misuse

  • Leaching of metals

  • Inappropriate plumbing and construction materials

PreviousA1.3 Assessment of water quality dataNextA1.5 Risk assessment

Last updated 8 months ago