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Discoloured Water

Frequently asked questions (FAQ)

Discoloured water can result from routine operations such as water main breaks or water main cleaning.

If you are experiencing discoloured water, check our water main activity or water main cleaning pages to see if there is nearby water main activity that has caused the discoloured water.

Discoloured water is not unique to Winnipeg. However, there was an unexpected increase in reports of discoloured water beginning in 2010.

We hired engineering consulting firms to assist in investigating the cause of the unprecedented increase in reports of discoloured water and to recommend measures to address discoloured water.

If you have concerns about your water other than discolouration, please refer to the Water Quality FAQs.

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About Discoloured Water

We recommend that you not use discoloured water for any purposes that require clean water, such as for drinking, preparing food and beverages, or laundry. We recommend this because discoloured water does not taste, smell or look pleasant, and it can stain clothes. Health officials do not recommend drinking discoloured water but if small amounts are consumed accidentally, no harm is expected.

To check if discoloured water has passed:

  • Turn on a cold water tap and let the water run for a few minutes. It is best to use a bathtub tap as there is no screen to trap any sediment. You can collect this water and use it to water your plants. Do not use a hot water tap because it could draw sediment into your hot water tank.
  • Catch some water in a light-coloured cup. If the water isn't clear, turn off the tap, wait 30 minutes and try again. Discoloured water usually doesn't last long. If your water still isn't clear after two to three hours, contact 311.

Check our water main activity or water main cleaning pages to see if there is nearby water main activity that has caused the discoloured water.

Discoloured water is from a change in flow of water in the system. This can cause sediment in the water pipes to loosen and be released into the water. The change of flow may be caused by activities such as water main breaks, firefighting or water main cleaning. Check our water main activity or water main cleaning pages for nearby water main work.

Discoloured water usually doesn't last long. Water main work in the area or water main cleaning may cause water to be discoloured for under an hour. A very large water main break may cause water to be discoloured for a couple hours. If your water isn’t clear after two or three hours, contact 311.

We will look at our water main activity and water main cleaning pages to see if there is an explanation for the discoloured water in your neighbourhood. If there is a high number of reports of discoloured water in a neighbourhood, we may flush the water mains in the area (i.e., open the fire hydrants and drain the water into the street). This will usually solve the problem.

In 2009, 311 was launched in Winnipeg and it marked a change in how we collected statistics on discoloured water reports. It was also the year before the new water treatment plant was brought online. Once the treatment plant was brought online in December 2009, there was an increase in discoloured water calls. We worked with consultants and they pointed to a buildup of mineral and organic material that was reacting with the higher quality of water and causing the discoloured water. We followed their recommendations to minimize the amount of disturbances customers would experience until the water quality stabilised. We saw a decrease in reports in 2011.

In 2012, there was another increase in discoloured water reports, which continued to increase significantly through 2013. We engaged a second consultant to help find a solution to the issue and they identified manganese as the cause of the increase of discoloured water complaints. The manganese was present in one of the key chemicals we use in the water treatment process. Immediately, we began to implement the consultant's recommended changes and saw a 46% decrease in discoloured water reports in 2014, compared with 2013.

Reports of discoloured water declined again in 2015 and 2016. In 2017, discoloured water increased as a result of major capital construction works.

Here is a chart of calls about discoloured water over the past few years, including calls up to April 30, 2018.

There are two main reasons why discoloured water increases in the summer:

  • In the spring and summer, there are more events that change the flow of water. This includes activities such as water main renewals, water main cleaning and connecting new water mains.
  • High levels of manganese are the major cause of discoloured water. In the summer, we use higher levels of ferric chloride, which is currently the main source of manganese. We have to add more ferric chloride to filter out natural material in the water that comes from Shoal Lake.

Cause of Discoloured Water

Elevated levels of manganese are the major cause of the significant increase in reports of discoloured water.

Manganese is a naturally-occurring element that can be found universally in the air, soil, and water. It is an essential nutrient for humans and animals, with humans getting most of their manganese through food.

Yes. We test for manganese in tap water on a monthly basis at six locations in the distribution system. The chart below shows minimum, average and maximum manganese levels tested at these locations from 2013 to present.

The data shows an increase in the manganese in the treated water since the water treatment plant began operations in December 2009.

Distribution system total manganese (Average of six distribution system locations)

The WHO's informal health guideline is 0.4 mg/L, based on continuous exposure.

Although manganese levels have risen over the years in Shoal Lake, Winnipeg's water source, the primary source of the increase in manganese is ferric chloride, used in one of the key treatment processes (coagulation) at the drinking water treatment plant. The materials used to manufacture ferric chloride contain manganese. Ferric chloride is approved for use in drinking water treatment by an American Water Works Association standard and is used in drinking water treatment plants across North America.

Ferric chloride is now a part of the water treatment process so we can lower the levels of chlorine and have fewer disinfection by-products. Disinfection by-products, which result from organic and inorganic material reacting, have been linked to negative health effects.

Manganese is an essential nutrient for physiological function, with most of the manganese in our body coming from food. Currently, the guideline for manganese, 0.05 mg/L, is set as an aesthetic (e.g., colour, odour, taste) objective in the Canadian drinking water quality guidelines. A maximum acceptable concentration to protect health has not been set. Studies on the possible health effects of manganese in drinking water are underway, but preliminary information indicates that any health effects would be at levels in drinking water that would be substantially higher (10 times) than those found in Winnipeg's drinking water, and would have to be associated with an exposure over a long period of time. For comparison, an average cup of tea may contain 0.4-1.3 mg of manganese and an average cup of apple juice may contain 0.2 mg of manganese.

The consultant has recommended a number of short and long term measures to reduce the level of manganese.

We have completed:

  • Switching to an alternate ferric chloride product that contains lower levels of manganese
  • A study by an independent consultant, whose scope included a review of the recommendations from the previous study to determine if there are any additional steps which could help to address discoloured water
  • Clean and inspect the three in-town water supply reservoirs to remove any buildup of manganese sediment
  • Modifying the existing water treatment process to improve manganese reduction by changing the filtration process

We continue to operate the water distribution system with the least amount of disruption (e.g., minimizing fire hydrant use by City forces and contractors, decreasing disruptions in flow direction and velocity).

These are recommendations from the consultant that are still in progress:

Recommended Measure Progress to Date (July 16, 2018)
Fast track the schedule of the annual Water Main Cleaning Program to clean all 2,637 kilometres in a three-year program, compared to the routine program of six years The 2014-2016 Water Main Cleaning Programs cleaned the entire water distribution system. The 2017 and 2018 programs continued with the fast tracked schedule flushing approximately 33 per cent of the distribution system in 2017 and 25 per cent of the distribution system in 2018.
Investigate an alternative drinking water treatment product (a coagulant other than ferric chloride), which requires a one-year pilot testing process A pilot plant was constructed and a consultant was engaged to oversee the testing and selection for an alternative coagulant. Testing and selection of an alternate coagulant is complete. Transition to a new coagulant is expected to be complete by the end of 2018.

Several of the recommendations are already complete, and the rest are underway. Testing an alternate coagulant product is expected to take until 2018. However, a gradual reduction in reports of discoloured water is expected as each recommendation is completed.

Citizens should expect that even after all the measures are in place, there will continue to be incidents of discoloured water from time to time, as is common in most public water systems. A change in the rate of flow of water in the distribution system during routine operations (e.g., turning valves on and off, opening fire hydrants, repairing water main leaks) can cause sediment and minerals in the water pipes to loosen or dissolve and be released into the water.

Water Quality

Although discoloured water may smell, taste or look unpleasant, none of the tests or information to date indicates any microbial issues with the water, such as presence of disease-causing bacteria, protozoa or viruses.

According to The Winnipeg Regional Health Authority: "Residents should not drink discoloured water or use it for purposes such as preparing food, beverages or infant formula; however, drinking small amounts of discoloured water should not pose a health threat if accidentally consumed."

Winnipeg's water is tested each step of the way, from Shoal Lake to the tap, to ensure safe, high-quality drinking water. We use nationally accredited laboratories for the tests and we do more sampling than required by our Operating Licence, including more bacteria and chemical testing. We have tested samples of discoloured water for:

  • bacteria (also an indicator of the presence of other micro-organisms, such as protozoa and viruses),
  • chlorine levels, to ensure ongoing disinfection,
  • the turbidity levels (clarity) of the water, and
  • chemical and physical parameters, including aesthetic objectives that affect taste and colour (e.g., iron and manganese).

Our water continues to comply with the requirements of the Operating Licence issued by the Provincial Office of Drinking Water, with Manitoba regulations, and with Guidelines for Canadian Drinking Water Quality. Our test results to date have shown that even when water is significantly discoloured, there is:

  • no evidence of bacterial or microbiological contamination,
  • chlorine levels that meet our Operating Licence,
  • turbidity levels higher in some samples, likely due to sediment in the water, and
  • iron and manganese levels higher than the aesthetic objectives in some results.

We continue to update the provincial Office of Drinking Water and the regional Medical Officer of Health on our findings.

Test results suggest that manganese is the primary contributor to discoloured water, although some discoloured water samples contain levels of iron higher than the aesthetic objective of 0.3 milligrams per litre. Test results at the water treatment plant show that iron in the distribution system is not coming from the plant. The consultant has suggested that iron at the tap is coming from deposits in the distribution pipes, which primarily originate from iron water mains. Testing shows that iron levels have been decreasing over time and that iron is not a major factor at this time.

Iron is an essential element in human nutrition. Iron in quantities greater than 0.3 milligrams per litre (mg/L) in drinking water can cause an unpleasant metallic taste and rusty color, and can stain laundry or household items. Currently, the guideline for iron is set as an aesthetic (e.g., colour, odour, taste) objective in the Canadian drinking water quality guidelines. A maximum acceptable concentration to protect health has not been set. Although ingesting large quantities of iron in any form (e.g., supplements) can be harmful, there is no evidence to suggest that concentrations of iron in Winnipeg's drinking water (discoloured or otherwise) would pose a risk to human health in the short or long term.

If you notice rust or iron on clothes when taking them from the washer:

  • Don't dry them in the dryer or rewash in hot water before treating the stains. Heat sets the stains and makes them difficult or impossible to remove.
  • Do not use chlorine bleach to attempt to remove rust stains. Chlorine will also make the stain permanent.
  • Rewash the clothes immediately in clear water with a heavy duty detergent.

There are a number of commercial stain removing products available that can remove rust stains (e.g., White Brite, RoVer Rust Remover, Rit Rust Remover, Red-B-Gone, Whink Rust & Iron Stain Remover, Super Iron Out Rust Stain Remover). Check to see if the removers are intended for white or colourfast fabrics only. Handle with care and use carefully according to the manufacturers' direction. Rinse the clothes thoroughly after treating with a stain remover.

There is also a number of eco-friendly stain removing alternatives.


No, because the cost is low and the discoloured water can be used for other purposes (e.g., watering plants or the lawn). A typical kitchen tap running for 10 minutes will use approximately 60 - 80 litres of water. This will add 24 - 32 cents to a utility bill, based on the current charge for water and sewer services at 4/10 of a cent per litre. The water is usually clear after running the tap for a few minutes.

Please contact 311, or check Risk Management's web page for more information.

More information

For more information on Winnipeg's drinking water:

Last updated: October 4, 2018