Hi all….Health Canada has been busy with new, reaffirmed, and proposed guidelines as well guidance documents this year. The latest is ‘Guidance on the use of quantitative microbial risk assessment in drinking water.’ It has been approved and is available for viewing/download at: https://www.canada.ca/en/health-canada/services/environmental-workplace-health/reports-publications/water-quality/guidance-qmra-drinking-water.html . The executive summary is below.

In addition:

  1. Health Canada has provided a link to the updated guideline summary table which can be a bit tedious to find:


  1. Comments on the reaffirmed MAC for E. coli of none detectable per 100 mL in drinking water are due by Aug 16: www.canada.ca/en/health-canada/programs/consultation-e-coli-drinking-water.html
  2. Comments on the proposed MAC and OG for aluminum are due Aug 30. A maximum acceptable concentration (MAC) of 2.9 mg/L for total aluminum in drinking water is proposed. An OG value of 0.050 mg/L is proposed for total aluminum to optimize water treatment and distribution systems: https://www.canada.ca/en/health-canada/programs/consultation-aluminum-drinking-water.html


Guidance on the use of quantitative microbial risk assessment in drinking water

Executive summary

“Quantitative microbiological risk assessment (QMRA) is an approach that can be used by regulatory agencies and drinking water authorities to quantify the health risks from microorganisms for water sources. It follows a common approach that includes hazard identification, exposure assessment, dose-response assessment and risk characterization. QMRA can examine the entire drinking water system, from the source water to the consumer, to understand the potential impacts on public health. Health Canada has developed and uses a QMRA model to support the development of drinking water guidelines for enteric viruses and protozoa. The model can also be used as part of site-specific risk assessments at drinking water treatment facilities.

QMRA can be a very useful tool in support of water safety management decisions. A well-formulated and thoughtful QMRA can offer important information on prioritizing hazards, identifying alternative risk management priorities and options, selection of appropriate interventions, cost-benefit analysis of risk management actions and setting of health-based performance targets. It is important to remember that QMRA does not calculate actual disease outcomes, but provides a probability that disease may occur based on the water quality and treatment system information entered.

The intent of this document is to provide industry stakeholders, such as provincial and territorial regulatory authorities, decision-makers, water system owners, and consultants with guidance on the use of QMRA to assist in understanding microbiological risks in Canadian water systems.”