Boil water alert guidance

A boil water alert should be considered where there is a risk that cannot immediately be rectified and consumers will be exposed to contaminated water.

This page forms part of the NSW Health response protocol for water utilities and public health units: Managing Pathogen Risks in Drinking Water.

On this page

1. Considering the need for a boil water alert
2. Issuing a boil water alert
3. Lifting a boil water alert
4. Incident debrief​ and reporting guidance.

Considering the need for a boil water alert

Under Section 22 of the Public Health Act 2010, the Chief Health Officer has the power to issue advice, for the benefit of the public, concerning the safety of drinking water and any possible risks to health. This advice may include a boil water alert. The supplier of drinking water concerned must issue the advice to the public in such form and manner directed by the Chief Health Officer. The power to provide this advice is delegated to PHU Directors.

The PHU should consult with the Water Unit, Environmental Health Branch, Health Protection NSW when considering a boil water alert.

A local water utility may issue a boil water alert of its own accord. However, before issuing a boil water alert, the utility should consult with their PHU.

The water utility, PHU, Water Unit and/or Chief Health Officer will consider the following when determining the need for a boil water alert:

• the findings of the water supply system investigation
• results of available water quality data (operational monitoring, field measurements and laboratory testing results)
• whether proper sample collection and analysis techniques were used
• whether samples are representative of water that is actually consumed
• the effectiveness of current treatment (including filtration and disinfection) to respond to the range of potential pathogens
• for a critical control point exception, consider the catchment condition, raw water quality and the likelihood of pathogens entering the drinking water supply.
• any complaints about water quality (including taste, odour and appearance) or health. Evidence of illness associated with this water supply
• the community impact of a boil water alert he community impact of a boil water alert (including adverse consequences such as scalds) where the cause can be resolved promptly.

Issuing a boil water alert

Once a decision is made to issue a boil water alert, the water utility must notify consumers urgently. The investigation should have confirmed where consumers are already exposed to the contamination, or when they will be exposed.

The conditions for lifting the boil water alert should be discussed with the PHU at the time that the alert is placed. These should include evidence of a sanitary survey, rectification of any problems, evidence that reservoir openings have been sealed and contamination removed, evidence that the supply system is operating normally (e.g. adequate filtration turbidity, adequate disinfection residual in distribution system), and clear microbiology sampling results.

NSW Health has standard words for a boil water alert due to:

• detection of E. coli, and
• poor raw water quality or when treatment or disinfection critical limits are exceeded.

In issuing a boil water alert the water utility should use the best means to communicate the information, possibly including:

• letterbox drops
• radio and television announcements
• door knocking
• signs on public taps and bubblers
• social media
• electronic roadside signs
• regional SMS services
• notify water carters and consumers who receive carted water.

Include the time and date in all updates, as messages are often repeated by others at a later time, especially across social media.

The water utility must:

• ensure vulnerable people and those with special needs receive the information they need to make themselves safe (e.g. direct communication with schools, hospitals etc.). Translated information should be available for culturally and linguistically diverse communities. Accommodation facilities should be reminded to provide the boil water advice to all consumers.
• notify consumers that may have received carted water drawn from the affected system.

The water utility, PHU and DoI Water should maintain close communication during the boil water alert to ensure all parties are kept up to date with findings and corrective actions.

The PHU should consider the need for enhanced surveillance for illness in communities where boil water alerts have been issued.

Lifting a boil water alert

The water utility must consult the PHU before lifting a boil water alert.

In lifting a boil water alert, the water utility should communicate the information in the same way the alert was issued. The water utility should also:

• include time and date in all updates, as messages are often repeated by others at a later time
• include information regarding the nature of the problem, how it has been fixed and assurance that the water is now safe
• notify consumers that may have received carted water from the affected system.

Incident debrief and reporting guidance

Directly following completion of the incident response, arrange a debrief discussion with relevant stakeholders, including all staff involved, NSW Health and DoI Water. The debrief should allow stakeholders to discuss the incident and address any issues or concerns. The aim of the debrief is to allow the utility, NSW Health and DoI Water to learn from the incident and improve operations and responses.

The debrief discussion should be followed up with a written summary report on the incident considering factors such as:

• the cause of the problem
• how the problem was first identified
• the most critical actions and pieces of information required to respond
• challenges in communication and how were they addressed
• how well the protocol was followed
• any necessary improvements to equipment, processes, SOPs or the incident management plan
• documentation of relevant information during the incident
• any actions to improve preparedness and planning for future incidents.

Utilities should consider the need to support staff who may feel a significant burden of responsibility for an incident (e.g. through counselling or an employee assistance program).

Further information

Contact your local Public Health Unit on 1300 066 055 and refer to:

• the NSW Health response protocol for managing pathogen risks in drinking water page and full NSW Health response protocol for water utilities and public health units: Managing pathogen risks in drinking water
• the response protocol flowchart
• sanitary survey guidance
• appendix on indicator bacteria
• NSW Health Naegleria fact sheet.

NSW Health has standard words for a boil water alert due to:

• detection of E. coli, and
• poor raw water quality or when treatment or disinfection critical limits are exceeded.