Water Quality Incident Response Procedure

Purpose. This procedure defines how the business responds to a drinking water quality incident from first detection through regulator notification, customer advice, corrective action and close-out.

1.What is an incident

A water quality incident is any event that indicates a risk to public health or that breaches a regulatory standard, including detection of E. coli in treated water or the reticulation, a critical control point breach, loss of disinfection, a contamination event in the network such as a backflow or a mains break near a sewer, an exceedance of a health-based guideline value, or a customer report of illness linked to the supply. Aesthetic exceedances such as colour or taste are managed as complaints unless they indicate a health risk.

2.Levels

Level 1 is an event contained within the plant or a single asset with no water supplied outside limits. Level 2 is an event where water outside limits has or is likely to have reached customers. Level 3 is a confirmed public health risk requiring customer advice such as a boil water advisory. The incident controller sets the level and can raise it at any time.

3.Immediate actions

The person who detects the event must notify the control centre immediately. The control centre operator must log the event in the WHS and Environmental Incident Register, notify the on-call water quality officer and the Control Centre and Water Quality Manager, who becomes incident controller, and secure the affected asset. Where the source is a treatment process, the plant operator must isolate the affected water where the procedure allows. Resampling must be arranged at the original site, upstream and downstream.

• Log the event with time, location and result
• Notify the incident controller
• Isolate or contain the affected water where possible
• Arrange resampling and chlorine residual checks

4.Notification

The incident controller must notify the health regulator as soon as practicable for any E. coli detection, health-based exceedance, loss of disinfection or suspected contamination, and no later than the time required by the regulations. Notification must include the location, the result, the population affected, the actions taken and the proposed next steps. The Managing Director must be told before the notification is made where time allows and immediately after if not.

5.Customer advice

A boil water advisory or a do not drink advisory will be issued when the regulator and the incident controller agree it is needed. The advisory must state the affected area in street terms, what customers must do, and when the next update will be given. It must be issued through the website, social media, media release, direct messages to registered vulnerable customers and door knocking where required. The customer team must brief hospitals, schools, aged care and food businesses in the area directly.

6.Corrective action and clearance

The incident controller must direct corrective actions such as flushing, additional disinfection, isolating a reservoir or repairing an asset, and must set the clearance criteria, usually two consecutive clear samples at least 24 hours apart with satisfactory chlorine residual. Advice will be lifted only with the regulator's agreement.

7.Close-out

A debrief must be held within ten working days. The Water Quality Incident Report Template must be completed, the risk management plan reviewed for any new hazard or control, and the incident register updated with actions, owners and dates.