Chloramines

What are chloramines?

Chloramines are a form of disinfectant used by Chester Metropolitan District. They are created when ammonia is combined with chlorine. 

The practice has been in use by water utilities since the 1930s and is widely used across the United States. Chloramines use is regulated by the Environmental Protection Agency (EPA)’s Stage 2 Disinfection Byproducts Rule.

Why use chloramines?

Chloramines as disinfectants provide long-lasting disinfection in large distribution systems as it does not dissipate as fast. By adding ammonia, the compound is  more stable, which also means we use less chlorine in the disinfection process.

Water disinfected with chloramines tends to stay fresh longer and have less residual chlorine taste and smell.

I got a notice saying chloramines are a contaminant. Why?

Companies that sell water filtration products often list chloramines as a “contaminant” as a scare tactic to try and sell their products. What these companies don’t want you to know is that water treated with chloramines does not need secondary filtration at your house. The water coming in through your tap is perfectly safe to use for drinking, cooking, bathing, or any other normal daily use (unless you make a habit of growing orchids, in which case distilled water is best for those because they’re highly sensitive plants).

But sometimes my water still smells like chlorine. Why does that happen?

A couple of times a year, CMD goes through a process we call a “chlorine burnout.” We turn off the ammonia feed at our water filtration plant and disinfect the system with a higher-than-normal dose of chlorine. This can cause an abnormally strong taste/smell, though the water is still safe to use. All of our disinfection processes follow all state and federal policies for safe drinking water.

The process is similar to disinfecting a pool. The high dose of chlorine “shocks” the distribution system to ensure the best possible water quality for all customers. During this time, residents may also see fire hydrants open and running near dead-ends and at the far edges of our water system. This is done to help pull the chlorinated water through the whole system, then to return chloramines after the burnout is complete.

Note: If you do notice a  strong chlorine smell, allowing water to sit for five minutes on your counter will allow it to dissipate. If you smell something other than chlorine, please let us know.

Where can I learn more about chloramines and water disinfection?

The best place to start is on the EPA website. They have information about chloramines, the Disinfection Byproducts Rules, and the Safe Drinking Water Act. There’s plenty of information to click through. 

https://www.epa.gov/dwreginfo/chloramines-drinking-water

As always, we’re also happy to answer any questions we can.