Chlorine and Chloramine in Tap Water: What They Do and What They Leave Behind

by AquaVerde Academy Editorial Team

AquaVerde Academy

Chlorine & Chloramine

What they do, and what they leave behind

Chlorine vs. chloramine

If your tap water sometimes smells like a swimming pool, chlorine or chloramine is almost certainly why. Both are added deliberately - they're the reason municipal tap water is safe from waterborne diseases like typhoid and cholera.

More than one in five Americans drink water treated with chloramine specifically. Chloramine provides longer-lasting disinfection as water travels through miles of pipes, and tends to produce fewer disinfection byproducts than straight chlorination - though it isn't free of tradeoffs of its own. Both are considered safe by the EPA and CDC at levels up to 4 parts per million; most municipal water runs well below that.

Key takeaway

The disinfectant itself isn't the main concern - it's what chlorine forms when it reacts with organic matter in the water.

Disinfection byproducts

Chlorine reacts with naturally occurring organic matter to form disinfection byproducts (DBPs) like trihalomethanes (THMs) and haloacetic acids (HAAs). Long-term exposure has been linked in epidemiological studies to an increased risk of bladder cancer. The EPA regulates THMs and HAAs, but these rules cover only a fraction of the 600+ DBPs identified in treated water.

Disinfectant	Main byproduct concern	Everyday tradeoff
Chlorine	Trihalomethanes (THMs), haloacetic acids	Stronger taste/odor, more DBPs
Chloramine	Nitrosamines, novel byproducts still being studied	Milder taste, harder to filter with basic carbon

Everyday effects

Effect	Why it happens
Taste and odor	Most common complaint, even within legal limits
Skin and hair dryness	Chlorine strips natural oils with repeated exposure
Respiratory irritation	Chloramine above 4 ppm can irritate eyes/nose
Pipe interactions	Chloramine can affect lead/copper leaching from old plumbing

How to reduce it at the tap

Activated carbon filtration is the most established method for reducing chlorine taste and odor, and can reduce certain DBPs depending on the media and contact time. Check whether your water is chlorinated or chloraminated - chloramine is harder to remove with basic carbon than free chlorine.

Frequently asked questions

Is chlorinated tap water safe to drink?: At U.S. municipal levels, yes. The consideration is long-term DBP exposure, not acute risk.
Does boiling remove chlorine?: It reduces free chlorine over time, but does little for chloramine or DBPs already formed.
Why does my water smell stronger sometimes?: Utilities occasionally switch to a temporary "chlorine burn" to control bacterial buildup in pipes.