Event: WATER MAY BECOME CONTAMINATED DURING DISTRIBUTION Possible hazards: Germs; chemical determinands Level of risk: Moderate S2.4.1 Backflow Inadequate prevention specifications Backflow devices at all for backflow prevention locations where prevention. inadequate backflow can occur and hazards to public health exist. (See water safety plan D2.4) S2.4.2 Specify the use of Distribution suitable materials system plans do Materials in construction of not meet the used in the distribution requirements of distribution system AS/NZS 3500.1: system National contaminate (See water safety plumbing and the water plan D2.1) drainage: Water supply. S2.4.3 Distribution Map of intended system analysis distribution Dead ends in designed to limit network is the areas of low flow, unsatisfactory, distribution and therefore and/or does not system stagnation of the allow for future water. growth. POORLY MANAGED SUPPLY Possible hazards: Germs; chemical determinands Level of risk: High S2.5.1 Inadequate or no Sampling ports sampling not agreed with Inability to HPOs as part of take samples design from certain specifications. locations S2.5.2 Determine Compliance monitoring with the No monitoring requirements for DWSNZ:2000 plan compliance with will not be DWSNZ:2000, plus achieved. any additional measurements. S2.5.3 Train someone to Compliance assess results to with the No determine when DWSNZ:2000 assessment of action is will not be results required. achieved. S2.5.4 Develop Water safety maintenance plan plan No appropriate to the contingency maintenance supply plans are likely plan to be used (See water safety frequently. plan 2.3)
Event: WATER MAY BECOME CONTAMINATED DURING DISTRIBUTION Possible hazards: Germs; chemical determinands Level of risk: Moderate S2.4.1 Backflow prevention inadequate Backflow prevention devices at all locations where backflow can occur and hazards to public health exist. (See water safety plan D2.4) Inadequate specifications for backflow prevention. S2.4.2 Materials used in distribution system contaminate the water Specify the use of suitable materials in construction of the distribution system (See water safety plan D2.1) Distribution system plans do not meet the requirements of AS/NZS 3500.1: National plumbing and drainage: Water supply. S2.4.3 Dead ends in the distribution system Distribution system analysis designed to limit areas of low flow, and therefore stagnation of the water. Map of intended distribution network is unsatisfactory, and/or does not allow for future growth. POORLY MANAGED SUPPLY Possible hazards: Germs; chemical determinands Level of risk: High S2.5.1 Inability to take samples from certain locations Inadequate or no sampling Sampling ports not agreed with HPOs as part of design specifications. S2.5.2 No monitoring plan Determine monitoring requirements for compliance with DWSNZ:2000, plus any additional measurements. Compliance with the DWSNZ:2000 will not be achieved. S2.5.3 No assessment of results Train someone to assess results to determine when action is required. Compliance with the DWSNZ:2000 will not be achieved. S2.5.4 No maintenance plan Develop maintenance plan appropriate to the supply (See water safety plan 2.3) Water safety plan contingency plans are likely to be used frequently.
new-supplies-feb14-v2.docx