Water Purification with Chloramines Frequently Asked Questions:

MWWS purchases treated water from The City of Mandan.

Starting April 10, 2006, the City of Mandan will change from using chlorine to chloramines to purify the water it produces. Chloramines are a combination of chlorine and ammonia used to kill potentially harmful bacteria in the water. The change to chloramines for disinfection purposes will result in a higher quality of drinking water.

Below are some things you might wish to know about the change.


Are Chloramines New?

No. Many cities in the U.S. and Canada have used chloramines for decades

Why is Mandan Making the Change to Chloramines?

The reason is to deliver water to our customers with the lowest possible levels of trihalomethanes (THMs).

What are Trihalomethanes (THMs)?

THMs are chemical compounds that are formed when chlorine mixes with naturally occurring organics in water. The U.S. Environmental Protection Agency (EPA) conducted tests which determined that chloroform (one of the THMs) is carcinogenic when consumed by laboratory animals in large quantities over a prolonged period of time, and is a suspected carcinogen for people. EPA set a standard of 80 parts per billion as the maximum level of THMs in drinking water.

Are Chloramines Safe?

Yes. Chloramines have been used safely in the United States and Canada for many years. EPA accepts chloramines as a disinfectant and as a way to avoid THM formations. Were it not for some kind of disinfectant in drinking water, disease-causing organisms such as typhoid and cholera could be carried in your drinking water. Chloraminated water is safe for bathing, drinking, cooking and all uses we have for water every day. However, there are two groups of people who need to take special care with chloraminated water: kidney dialysis patients and fish owners.

Why Do Kidney Dialysis Patients Have to take special Precautions?

In the dialysis process, water comes in contact with the blood across a permeable membrane. Chloramines in that water would be toxic, just as chlorine is toxic, and must be removed from water used in kidney dialysis machines. There are two ways to do that – either by adding ascorbic acid or using granular activated-carbon (GAC) treatment. Medical centers that perform dialysis are responsible for purifying the water that enters the dialysis machines.

Is it safe to drink water containing Chloramines?

Yes. Everyone can drink water that’s chloraminated because the digestive process neutralizes the chloramines before they reach the bloodstream. Even kidney dialysis patients can drink, cook and bathe in chloraminated water. It’s only when water interacts directly with the bloodstream-as in dialysis or in a fish’s gill structure-that chloramines must be removed (See question HOW DO CHLORAMINES AFFECT FISH?).

What will water taste like with Chloramines?

If you notice any change at all, you may find the water has less of chlorine odor or taste.


How do Chloramines affect fish?

Chloramines are toxic to fish and must be removed from water, just as chlorine is toxic and must be removed. You may not have had to remove chlorine from your aquarium water, however, because it disappears rapidly on it own. This is not the case with chloramines and steps should be taken to remove chloramines. Most pet stores have sold dechlorinating agents for years and, generally, have recommended using them. The chemicals used to remove chlorine should work just as well for chloramines.