City Conducting Water Main Flushing with Chlorination

On April 18, 2016, the City of Duncan will begin its Annual Water Main Flushing Program.

The City will be using its newly constructed Emergency Chlorination System, which was built in consultation with the Vancouver Island Health Authority, for the purposes of protecting the City’s water quality in the event of an emergency and to maintain water quality through the annual water main flushing.

This new system will be used for the 2016 annual water main flushing period, which will run from April 18, 2016 – May 6, 2016. During this time, some users may notice an odor or taste of chlorine or reduced pressure and discolouration of the water. If you are bothered by chlorine odour or taste, some solutions include: installing an activated carbon filter at your tap, using a carbon filtering water carafe, or filling a pitcher of water and setting it aside for several hours while the chlorine dissipates (transferring the water rapidly between two pitchers can accelerate chlorine dissipation).

Commercial establishments such as laundromats, hair salons and care facilities, or any concerned citizen, can contact the Public Works Department at 250-746-5321 to ask for advance notice of flushing in their area. You may also refer to the list of frequently asked questions on the back of this notice for more information.

The City’s water undergoes analysis regularly and continues to meet or exceed all standards for safe drinking water. The City will continue to provide the Duncan water system users with the best drinking water possible and to protect our users in the event of a poor water quality occurrence. Staff appreciate your patience and will make every effort to minimize any inconvenience.


Len Thew, Operations Manager – Public Works

* Note: In order to reduce costs, this notice has been distributed using bulk mail. If you are not on the City of Duncan water system, please disregard.

Frequently Asked Questions

Q. What is chlorine?

A. Chlorine is a common element in nature, where it is usually found combined with other elements. The largest amount of chlorine on earth is found in the oceans as sodium chloride or salt. In fact, salt and water are the most common ingredients used to manufacture the chlorine used in your drinking water.

Q. Why is chlorine added to drinking water?

A. Chlorine is a strong disinfectant that is able to kill many types of bacteria, viruses and parasites (pathogens) that cause water-borne infections. Some water-borne infections can cause severe illness and even death. Water suppliers add chlorine disinfectants to drinking water to kill pathogens.

Chlorine disinfectants were first added to a permanent water supply in North America in 1908. By the 1920s, thousands of American cities were using chlorine disinfectants to treat their drinking water supplies. There was a drastic reduction in water-borne infections, such as typhoid fever and cholera, and infant mortality.

Currently, most cities or towns in North America use chlorine disinfectants to treat drinking water.

Q. How is chlorine added to drinking water?

A. There are many ways to add chlorine to drinking water because there are many different chlorine disinfectant products available on the market. These products can take the form of a solid, liquid or gas depending on the other ingredients. However, they all work in a similar way once added to water. This is why they all get the generic labeling of “chlorine.”

The City of Duncan chose injection of liquid chlorine based on a number of factors, including cost and ease of handling.

Q. Can the City of Duncan use anything else to disinfect my drinking water?

A. Ultraviolet light and ozone are capable of disinfecting drinking water. However, they do not provide protection once the water enters the pipes that bring water to your home. Only chlorine disinfectants are able to provide some continued protection of the water after entering the pipes.

Another reason chlorine disinfectants may be used is they are typically easier to handle and/or less expensive than other disinfectants. This makes them a preferred choice of cost-conscious water supply system operators and individual homeowners with their own water supply systems.

Q. Can the chlorine added to my drinking water harm me?

A. There is no evidence that chlorine disinfectants are harmful to people when used on their own in the small amounts needed for drinking water disinfection. In addition, Health Canada reports no harmful health effects in people that drink water with large concentrations of chlorine (50mg/L) over short periods of time. The City of Duncan will be using a concentration much, much lower than 50 mg/L over a short period of time to keep
your drinking water safe.

Q. Will chlorine be used continually in my water?

A. The City of Duncan intends to only use chlorine once per year in conjunction with the annual water main flushing program or in the event of an emergency.