Chloramine
Chloramines are compounds formed when free chlorine reacts with nitrogen-containing compounds in pool water.
Definition
Chloramines are compounds formed when free chlorine reacts with nitrogen-containing compounds in pool water. They are the primary cause of pool odour and eye irritation.
Typical Values: Action threshold: 0.5 ppm combined chlorine
In Plain Language
The main chloramines in pool water are monochloramine (NH2Cl), dichloramine (NHCl2), and nitrogen trichloride (NCl3). Monochloramine is relatively mild. Dichloramine and nitrogen trichloride are volatile and highly irritating. All chloramines are far less effective disinfectants than free chlorine. Combined chlorine = the sum of all chloramine species in pool water.
Why It Matters
Chloramines are the direct cause of the symptoms most people attribute to too much chlorine: red eyes, skin irritation, and strong chemical odour.
Typical Values
Action threshold: 0.5 ppm combined chlorine
Last reviewed: 2026-06-01