Adverse Water Quality Incidents


Measure the effectiveness of Hamilton Water’s treatment systems for the provision of clean, safe drinking water.  Standards for drinking water quality are set and enforced by the Safe Water Drinking Act. The City of Hamilton’s drinking water regularly meets all Ontario Drinking Water Standards. Water samples are collected from approximately 113 locations.

Story behind the numbers

The current target for adverse water quality incidents (AWQI) is 0. All AWQI are reportable to the Ministry of the Environment and Climate Change, however once the AWQI is triggered, further sampling dictates whether it is confirmed or unconfirmed.  If the AWQI is confirmed, investigative and preventative actions are required to ensure the safety of the drinking water.  If the AWQI is unconfirmed no further action is required. The AWQI indicator is influenced by seasonality, external service levels and other factors such as inclement weather and construction activity.

Performance improvements

Hamilton Water has a number of initiatives to ensure requirements are met. These include:

  • Optimization of the water distribution sampling and testing program to meet and exceed the Ontario Drinking Water Standards
  • Development of an Asset Management Plan to rehabilitate and replace aging infrastructure.

Previous years, 12 months data. 2018 data from January to March.

Adverse Water Quality Incidents

Year Status Q1 Q2 Q3 Q4 Total
2015 Confirmed   4 2 0 6
2015 Unconfirmed 1   2 1 4
2016 Confirmed 0 1 1 3 5
2016 Unconfirmed       1 1
2017 Confirmed 0 0 1 0 1
2017 Unconfirmed   1 2   3
2018 Confirmed 0 0 2   2
2018 Unconfirmed 1 1 2   4
Total           26