Protocols for Adverse Water Quality

What are examples of Adverse Water Quality Incidents?

  • Unsatisfactory bacteriological test results (e.g. presence of E. Coli)
  • Inadequate disinfection (e.g. insufficient contact time, low level of chlorine)
  • Maintenance or repair of water distribution system (e.g. main break)
  • Compromised integrity of water supply system due to disaster
  • Outbreak of waterborne disease in the community

Based on the severity of the incident, a water use restriction (drinking water advisory) may be issued to affected customers.  A drinking water advisory can be issued by either of the following authorities:

  • Owner or operating authority of the drinking water system (municipal or non-municipal)
  • Eastern Ontario Health Unit

However, it is the responsibility of the owner of the drinking water system to notify all users, including other communities that receive water from the affected drinking water system. Regardless of the entity making the decision to issue an advisory, it can only be lifted by the Eastern Ontario Health Unit, or with its approval.

Response to an Adverse Water Quality Incident

There are three types of drinking water advisories. Depending on the problem affecting the water supply, one of the following water advisories may be issued:

  • Boil water advisory
  • Do not drink water advisory
  • Do not use water advisory

Boil Water Advisory

A boil water advisory is issued when authorities suspect or have confirmed the presence of harmful microorganisms in the drinking water supply (e.g. E. coli). Water must be brought to a rolling boil for at least one minute before use and consumption.

Do Not Drink Water Advisory

A do not drink water advisory is issued when authorities suspect or have confirmed the presence of unacceptable levels of chemical contaminants in the drinking water supply that can pose health risks if ingested (e.g. hydrocarbons). Water may be used as indicated for other purposes (such as taking a shower or doing laundry), but it cannot be consumed or used for food preparation. Boiling the water will not render it safe, as it will not remove the chemical contaminants.

Do Not Use Water Advisory

A do not use water advisory is issued when authorities suspect or have confirmed the presence of chemical/radiological products or contaminants in the drinking water supply (e.g. chemical contaminants infiltrate the water supply after an industrial accident). Water must not be used for any purpose and skin contact should be avoided.

Responsibilities

The responsibility for making sure that drinking water supplies are safe is shared between the owner of the drinking water system, the operating authority of the drinking water system, the Eastern Ontario Health Unit (EOHU) and the Ministry of the Environment and Climate Change (MOECC).

Owner of the Drinking Water System

The owner of a drinking water system, or its designated operating authority, oversees the day to day operations of the treatment facilities. The owner:

  • Ensures that the water system is operated in accordance with relevant protocols, guidelines and legislations so as to provide safe drinking water to all users
  • Notifies water users, the EOHU and the MOECC as soon as it becomes aware of any problem that may result in the drinking water being unsafe
  • Issues a drinking water advisory when a water supply or a source for a water supply is or is suspected of being contaminated
  • Informs users as soon as possible when drinking water advisories are issued and lifted
  • Provides regular updates to affected users after the initial notification, and until the advisory is lifted

Eastern Ontario Health Unit

The EOHU:

  • Receives notices of adverse water quality reports and responds as necessary
  • Ensures that adequate steps are taken to protect the users of the water drinking system
  • Issues a drinking water advisory when a water supply or a source for a water supply is or is suspected of being contaminated
  • Lifts the drinking water advisories when conditions return to normal and the water is safe for use and consumption

Ministry of the Environment and Climate Change

The MOECC:

  • Regulates and issues permits, licenses and approvals for the construction and operation of municipal drinking water systems
  • Monitors and ensures that the infrastructures and operational procedures of the water facility are sufficient to deliver safe water
  • Inspects all municipal drinking water systems annually, and conducts risk-based inspections of non-municipal drinking water systems to assess compliance with the Safe Drinking Water Act (SDWA)
  • Responds to high-risk adverse drinking water quality incidents and drinking water emergencies to ensure appropriate action is taken to ensure regulated drinking water systems supply safe drinking water
  • Works with other authorities during a drinking water advisory
Eastern Ontatio Health Unit / Bureau de santé de l'Ontario