Water quality

During COVID-19 closures, many buildings had low or no water use for an extended period. 

While municipal tap water continues to be safe to drink from a reliable source, closures pose a risk for stagnation and water quality within buildings.

Property owners and managers are responsible for water quality in their buildings. Flushing clean, fresh water through pipes and fixtures is a first step, though larger buildings may require more advanced techniques.

For full details download our fact sheet (PDF) and follow the guidelines set out by the Canadian Water and Wastewater Association.


Learn how to identify and respond to water quality problems, and find how the city maintains a safe drinking water system.

Report persistent water issues to us by phone at 519-886-2310. Subscribe to service alerts for water quality warnings.

We work with the Region of Waterloo to maintain our water system. The region is responsible for water supply and wastewater treatment. The city is responsible for the distribution of drinking water and the collection of wastewater. 


On this page

  1. Recent discoloured water events
  2. Clearing discoloured water
  3. Low pressure
  4. Boil water advisories
  5. Water quality management

Recent discoloured water events

Water use patterns have changed across the city with people staying home during the day. We are experiencing more discoloured water due to changes in demand and flow patterns, combined with the high temperatures and low rainfall this summer.

The discoloured water is from natural iron and manganese minerals and is not a health risk. It can be unpleasant to look at, or taste. Discoloured water can impact the performance of your home filtration system. We recommend bypassing your home filtration systems.

Discoloured water events may ease as these changing water use patterns and demands return to historical levels.

Clearing discoloured water

Discoloured water is usually caused by minerals naturally found in groundwater or from the corrosion of older iron pipes in the water distribution system. These minerals can be disturbed during activities such as watermain cleaning or fire hydrant maintenance. Iron pipes are being phased out of our water system to avoid future corrosion issues.

We recommend you do not drink discoloured water. To clear it from your water line, run the cold water tap in your home for five minutes. If that does not work, wait an hour and try again. Report persistent issues to our water team at 519-886-2310.

Low pressure

If water pressure is lower than usual, there are a number of things you can do:

  • if only hot water is affected, contact your water heater provider or a plumber
  • if only softened water is affected, put your softener on bypass and contact a plumber
  • check your water valve to make sure it is fully open. It is found where water enters the house
  • if your neighbours are also experiencing low pressure, contact us at 519-886-2310 for assistance

Boil water advisories

There are no active boil water advisories in Waterloo. Subscribe to our service alerts page for water alerts and instructions on what to do if an advisory comes into effect.

Water quality management

Drinking water quality management system

We're accredited by the province as the city's water operating authority, with a municipal drinking water license and drinking water works permit. Our system for ensuring water quality meets the requirements of Ontario's Drinking Water Quality Management Standard. Information about the system is described at length in our operational plan (PDF). 

Water quality reports

Lead testing

Prior to the 1950s, lead pipes were used to connect buildings to the watermains. While we work to remove them during road reconstructions we have a proactive program that analyzes lead levels in our drinking water. This program meets provincial requirements for drinking water quality. A summary of last year's result is provided in the water quality reports tab above.

We test water samples throughout our water distribution system every six months and in private homes built in 1989 or earlier every six months. To volunteer to have your home's water tested for free, contact our water team at 519-886-2310. Availability is limited so volunteers will be taken on a first come, first served basis.

If unsafe levels of lead are detected, we will retest your home to confirm results and provide further information from the Region of Waterloo's Public Health (PDF) on how to reduce your lead exposure from drinking water. 

Additional information on lead in drinking water can be found by visiting Health Canada.