Frequently Asked Questions

The answers provided below have been developed to answer Casselman's questions about the clarity of the water.

If your question is not answered below, send it to us using the following form: 

Frequently Asked Question - Municipality of Casselman

Is the Municipality going to give us a rebate on our water and sewer bills?

According to the Ontario Municipal Act, the water bill must cover treatment, maintenance, repairs and improvements to infrastructure, as well as sewers. Water quality is not a factor in calculating the billing rate. Your bill shows a base usage charge for a minimum of 10 cubic meters per month. Each additional cubic meter of water is billed at a cost of $2.57. If your consumption remains within limits, your bill is approximately $90 per month.

What is the obligation of the Municipality when it comes to the municipal drinking water?

Under the Ontario Clean Water Act and our own by-laws, the Municipality, as the owner of the drinking water system, is responsible for ensuring potable drinking water is provided to residents in accordance with provincial regulations. On behalf of the owner, OCWA operates and maintains the water treatment facility and the water distribution system. Casselman’s Drinking Water System is inspected annually by the Ministry of the Environment, Conservation and Parks to ensure compliance with the regulations.

As per its by-law, the Municipality of Casselman must deliver drinking water from the treatment facility’s intake to the service connection located in the distribution system at your property line.  

Should I buy a water filtration system for my home?

We advise residents to exercise caution when considering unnecessary purchases of water filtration systems. While we understand the importance of health and safety, it is essential to make informed decisions based on verified information.

What is the Municipality doing about the manganese in the water?

Historically, the Casselman Water Treatment Plant (WTP) has experienced challenges in reducing total Manganese levels below aesthetic guidelines at various times during the spring and summer seasons. The peak raw water manganese concentrations typically occur in the warmer summer months when the raw water temperature is higher. This is because during higher temperatures, dissolved oxygen levels at the bottom of the river decrease, causing insoluble manganese oxides to become soluble through bacterial action and leach out of the sediments. While OCWA is trying to optimize the best performance out of the existing infrastructure, the facility’s current processes have limitations on its capacity to treat incoming raw water quality.

The Municipality received funding in 2022 under the Investing in Canada Infrastructure Program to investigate options for treatment of Manganese in the drinking water system.  J.L. Richards & Associates Limited (JLR) has been retained by the Municipality of Casselman to provide engineering services for the design and tender documents associated with upgrades to the Casselman Laval Street Water Treatment Plant (WTP) to address the influent manganese (Mn) concentrations, which are not currently adequately reduced at the WTP. 
The Municipality is considering all options including the commencement of an Environmental Assessment (EA) process to investigate solutions regarding treatment and hydraulic capacity. 

In addition to the steps already taken with the Ontario Water Agency and the Walkerton Expertise Center, the Municipality of Casselman has engaged the professional services of Mr. Bill Dallala, a chemical engineer specializing in water quality, to strengthen our efforts in water management. During his visits to our facilities, detailed analyses and inspections of equipment configuration will be conducted, along with evaluations related to oxidation and filtration. Following this, the municipality will receive a comprehensive report with appropriate recommendations. We are actively committed to continuously improving our approach to ensure a safe and reliable water supply.

Why is the Municipality not providing water to residents?

The Municipality upholds democratic principles and ensures transparent decision-making through the council. Budgetary decisions undergo thorough discussion and approval by elected representatives. The Municipality adheres to water safety guidelines recommended by the Eastern Ontario Health Unit. Residents' health and safety are a top priority, and decisions are made collaboratively for the benefit of the community. Fiscal responsibility is upheld, and the Municipality remains committed to unity and engagement with the council and the public. Water quality is closely monitored, and experts are consulted to address any challenges and ensure the well-being of residents.

What are the impacts of water line flushing?

Water line flushing can cause sediment stirring for a few minutes. Customers who draw water during flushing in their area may notice reddish-brown colored water. If this occurs, run your taps until the water runs clear. Water line flushing helps ensure water quality and prevents random episodes of rusty water during high water demand, caused by significant firefighting efforts or water line breaks. During water line flushing, some customers may also notice a reduction in water pressure and flow rate.

How often is water line flushing conducted?

Water line flushing takes place twice a year for a duration of one month. The work is typically carried out between 8 a.m. and 4 p.m.

Why does water line flushing give my water a rust, reddish-brown, or tea color?

Sometimes, water line flushing can temporarily give water a rusty color as iron and other mineral deposits present in the water pipes are stirred up.

Is discolored water from water line flushing safe to drink?

There is no health risk associated with discolored water. The water can be safely used and consumed during water line flushing, but it may stain laundry.

What should I do if I see discolored water coming from my tap?

If you see a reddish, yellow, or brown tint in your tap water, do not worry. Run a cold water tap for a few moments, and its clarity should return.

Frequently Asked Questions - Eastern Ontario Health Unit

What is manganese and how am I exposed to it?

Manganese is an essential nutrient (mineral) for all living organisms and is found naturally in the environment. It can be present in air, food, water, soil and rocks. Manganese gets into drinking water sources when water dissolves minerals that contain manganese. Consuming a small amount of manganese from food or water is needed to stay healthy.

Is exposure to manganese in water a health concern?

For a long time, manganese was only considered an aesthetic issue in drinking water (e.g. causing stains on laundry, plumbing fixtures, etc.). However, recent research suggests that exposure to high levels of manganese in drinking water for extended periods may cause adverse health effects, primarily on the central nervous system. This new information was used to revise Health Canada’s guidelines for manganese in drinking water.

How much manganese in the drinking water is considered safe?

According to Health Canada’s new guidelines, drinking water that has manganese levels at or below 0.12 mg/L is considered safe for consumption. This maximum acceptable concentration (MAC) of manganese is based on scientific research and includes safety factors to ensure that sensitive individuals, including infants, are protected even if exposed to elevated levels of manganese for long periods of time. Concentrations at or below the MAC are not associated with increased health risks in any individuals.

At what point does exposure to manganese in drinking water become a health risk?

Studies suggest that for adults and older children, drinking water with a manganese level higher than 1mg/L for more than 10 days may present a health hazard. (Note: For children less than 6 months of age, the level is less than 0.3 mg/L. For this reason, we recommend that another source of water should be used for dilution or reconstitution of formula for babies under 6 months of age who are exclusively formula fed.)
Although the level of manganese in the Casselman municipal drinking water is currently higher than the Health Canada guideline of 0.12 mg/L, there has only been one day in the past month where it has exceeded 1mg/L: 1.002 mg/L on July 17th, 2023. Note that on July 18th and 19th, the manganese levels dropped significantly to 0.24 and 0.105 mg/L, respectively.
Given that the water meets all Ontario drinking water standards, it remains safe for adults and older children to consume despite the discoloration. The EOHU is monitoring the situation on a daily basis. Should the levels reach and remain higher than 1 mg/L for more than 10 days, at that point the EOHU will recommend an alternate drinking water source for everyone.

What health effects can be caused by drinking water with high levels of manganese in it?

Exposure to high levels of manganese in drinking water over an extended period of time could potentially lead to the development of learning and behavioural problems, and deficits in memory, attention and motor skills.

Why are infants at higher risk than older children and adults?

Infants are at higher risk from exposure to high levels of manganese in drinking water because their brains are developing rapidly, they drink more water relative to their body weight, they absorb more manganese and are less able to remove it from their bodies in comparison to older children and adults. Infants consuming formula prepared with drinking water that has high manganese levels are particularly at risk. For this reason, since the current levels of manganese in the municipal drinking water are above the Health Canada guideline of 0.12 mg/L, it is recommended that an alternate source of water (e.g. bottled water) be used to prepare infant formula for babies less than 6 months of age who are exclusively formula fed.
Older children and adults, including expectant mothers, are at lower risk because they absorb a much smaller amount of manganese from their food and water than infants.

Should I use tap water to bottle-feed my infant?

Formula that is mixed or diluted with tap water can be a source of exposure to manganese for bottle-fed infants. Since the current levels of manganese in the municipal drinking water are above the Health Canada guideline of 0.12 mg/L, it is recommended that an alternate source of water (e.g. bottled water) be used to prepare infant formula for babies less than 6 months of age who are exclusively formula fed. Note that when the manganese levels reach and remain consistently at levels below 0.12 mg/L, this recommendation will be removed.

If I am pregnant or breastfeeding should I use another source of water for drinking?

Manganese absorption and excretion is managed by the mother’s body. Adults, including expectant or breastfeeding mothers, absorb a much smaller amount of manganese from their food and water than infants. As a result, developing fetuses are less sensitive to manganese in drinking water than infants.
Breastfeeding is not likely to be a significant route of exposure.

Does boiling the water remove the manganese? Is it safe to cook with the water?

Boiling does not remove the manganese from the water. Boiling the water for an extended period is not recommended. However, it is safe to cook as usual with the water, although there may be an alteration in the taste of the food.

If levels of manganese in my water are above the guideline value, can I still use it to bathe, shower and wash hands?

Exposure to manganese through skin contact is not harmful. The exposure risk from handwashing, showering, or bathing with water containing elevated manganese is unlikely to be significant.

If the manganese levels increase to the point that the water is no longer considered safe to drink, what actions will be taken to protect residents?

The EOHU is monitoring the situation on a daily basis. Should the levels reach and remain higher than 1 mg/L for more than 10 days, at that point the EOHU will recommend an alternate drinking water source for everyone.

Where can I get more information about manganese in drinking water?

For updates to this Frequently Asked Questions document, please visit the Eastern Ontario Health Unit’s website at
Additional information can be found in the resources below:
Water Talk – Manganese in drinking water (
Frequently Asked Questions: MANGANESE (

Frequently Asked Questions - Ontario Clean Water Agency

Are you planning on flushing the water lines to decrease the levels of manganese in the water system?

OCWA flushes the distribution system on a scheduled basis. Flushing of the entire distribution network is completed twice annually in May and October. Flushing of dead ends in the system takes place routinely in the summer months, from June through September. During the week of July 17th, OCWA began flushing in the system to help reduce some of the sediment deposits caused by the high level of manganese. We have continued with the flushing this week and will monitor to see if this activity helps reduce some of the issues and proceed accordingly.

What is the difference between clear and unclear manganese? How does it relate to the sediments in the water?

The source water for Casselman’s Water Treatment Facility contains soluble minerals such as calcium, magnesium, iron, and manganese. When treatment is applied to the water, it oxidizes dissolved minerals, causing some of them to precipitate out of solution as mineral oxides. These insoluble mineral oxides may be noticed by residents as sediment in their water and contribute to discoloration of the water. Although unpleasant, the sediments and discoloration are an aesthetic issue. Hard water scale and sediments may affect household equipment such as your hot water tank. Routine maintenance on your household equipment in accordance with the manufacturer’s recommendations should be performed. The intervals for such maintenance can vary depending on the water quality.

How long can we anticipate the water discoloration issue will last?

Fluctuations in the raw water chemistry of the source water for the treatment facility cannot be accurately predicted in advance. Testing and consultations are taking place regularly to optimize water quality and address concerns. Communication will continue to be provided to residents to address concerns as they arise. The concentration of manganese in raw water fluctuates seasonally and there are typically more water quality issues in the summer months, especially when the weather is very hot and there is limited rainfall.

Where is the OCWA report for June? We are almost at the end of July.

As it does take time to pull the various reports and to compile and verify data, the monthly reports for the Municipality are due by the end of the following month for the preceding month. June’s report will be submitted to the Municipality by the end of July. Before the report is publicly released, it must go before council.

Can we find out exactly what the daily manganese numbers are in Casselman?

Due to fluctuating conditions in the South Nation River, manganese levels in the raw water are constantly changing. OCWA is continually conducting testing at the plant to optimize the system in response to the changing conditions. Consultations regarding manganese levels have been taking place routinely between the Municipality, OCWA representatives and regulatory bodies including the Ministry of the Environment, Conservation and Parks (MECP) and the Eastern Ontario Health Unit (EOHU). Relevant information is being communicated by the Municipality to residents regarding the situation based on these discussions.

Who is the Ontario Clean Water Agency (OCWA)?

The Ontario Clean Water Agency (OCWA) is an Agency of the Province of Ontario established in 1993. We provide various water and wastewater services, including the operation, maintenance, and management of water treatment plants, wastewater treatment facilities, and related infrastructure. Our agency works with municipalities and other clients to ensure the delivery of clean and safe drinking water, as well as effective wastewater management throughout the province.
OCWA is widely trusted due to its extensive experience, proven track record, and accountability as a Crown corporation, ensuring reliable and high-quality water and wastewater services. Across Ontario, OCWA operates more than 800 facilities that are engineered, designed and constructed by system owners for the safe treatment and delivery of water. OCWA’s Annual Reports are available on our website.
OCWA has been operating the Municipality of Casselman’s drinking water system since 2017 and its wastewater system since 2021. OCWA’s reports for these systems are available on the Municipal website. There are also free copies available for consultation at the Municipal Office.