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I often hear “Calgary doesn’t have drinking water problems” when talking to people about potable (drinking quality) water in Calgary buildings. Most often, it’s based on the perception that Calgary is too modern to manifest the water infrastructure problems of older cities. Unfortunately, that’s not entirely accurate.

It’s certainly true that when the water leaves a City of Calgary treatment plant, its quality is very high indeed. In fact, it’s still usually pretty darned high once it gets to the property line of whatever building is consuming it. It’s what happens after it crosses the building’s property line that’s the concern.

As the World Health Organization notes:

“A general perception can be that water systems in buildings connected to public supplies are safe, ignoring the potential for contamination (both chemical and microbial) and growth of waterborne opportunistic pathogens within the building water systems.” [1]

In other words, it’s issues with the building’s own water delivery system can create adverse health effects. Worse, it’s generally not perceived as a potential problem by building management – although that is starting to change.

In general, contamination arises from one or more of three causes:

  • Direct contamination. This is from faults in the building’s own water systems. Examples include the failure of backflow preventers; deadheads left in place after piping revisions to the water system; or leaching from pipe and fitting corrosion (e.g. – copper, lead, and other metals) are typical sources.
  • Indirect contamination. This is usually from cross-connections between drinking-water systems and contaminated water or chemical storage locations;
  • Indigenous microbes. This is from the growth of microbes such as Legionella in the building’s own piping and fixtures.

What to do?

To one extent or another, building owners should have a water safety plan (WSP) in place. This can be relatively simple for smaller or less complicated buildings but may be quite extensive for larger or specialized use facilities.

1.   Risk Assessment

The first step is to conduct a risk assessment. This means identifying specific potential hazards and ranking the likelihood and severity of exposure. The previously referenced World Health Organization document is a good resource for this.

You may also want to conduct a specific risk assessment to see if your building has an increased risk for Legionella. The US Centres for Disease Control (CDC) has a quick questionnaire you can fill out online.[2]

Once the risk assessment has been completed, a program to reduce the risk for the identified areas of concern should implemented.

2.   Risk Mitigation

Risk mitigation (reduction) means implementing a combination of activities to reduce the risks for the identified risk areas. These may include activities such as education and changes to your policies, O&M practices (e.g. regular flushing), or your actual infrastructure (e.g. – removal of deadheads).

3.   Regular Testing

Only after the risk assessment has been completed, building management should consider conducting regular laboratory testing. The key here is that testing should be targeted to the risk areas identified. Testing willy nilly is better than nothing, but inefficient and potentially dangerous, since high risk areas are likely to me missed.

In addition to identifying and managing risks, having a well thought out and documented record of historical testing can be extremely useful in reducing future liability.

The exact contaminants to test for should be determined by the risks identified in the risk assessment but would typically include at least the following subset of the Health Canada drinking water guidelines[3]. You’ll typically see at least:

  • Turbidity (cloudiness) and total dissolved solids.
  • Trace metals such as lead and copper.
  • Microbiologicals such as coliforms and legionella.

Several qualified testing laboratories are available in Calgary to conduct this testing – just be sure they’re currently CALA[4] or equivalently accredited.

Sustainability Programs

It’s also worth noting that BOMA BEST, WELL, and Fitwel all have points available for potable water testing. For BOMA BEST, it’s worth noting the points are only available as part of W6.2 – Innovation and are not prescriptive as to the requirements.


We’re fortunate in Calgary to have an extremely high quality of water available to us from the municipal supply. It’s also worth remembering that well run and maintained buildings in Calgary will not usually have significant potable water issues.

Still, it would be prudent take the trouble verify (and document) that our buildings do not have or develop any such problems.

Cheers, and stay healthy,

Curt LaMontagne, Principal Consultant – C5 PLUS

[1] World Health Organization, Water Safety in Buildings (2011), p. 6


[3] Guidelines for Canadian Drinking Water Quality.