What’s in your city’s water?

When we talk about Chlorine vs. Chloramine we are really talking about the choice of residual disinfectant, which is the chemical that travels with your water through miles of pipes to reach your tap. Most US cities still use chlorine as their residual, but more are switching to chloramine. Chloramine persists in the water longer. It is a more stable molecule and will not naturally dissipate into the air or aggressively react with every surface it encounters. More persistence means better disinfection coverage from the treatment plant all the way to your home.

But that stability also makes chloramine significantly harder to remove than chlorine. Both compounds are removed using activated carbon filtration, but chloramine removal requires a special type called catalytic carbon. Standard carbon filters designed for chlorine removal will not effectively remove chloramine.

Why it matters

• Filter selection: standard carbon for chlorine; catalytic carbon for chloramine
• Aquarium and fish pond owners: chloramine cannot be neutralized by letting water sit - a dechlorinator rated for chloramine is required
• Home brewers: chloramine cannot be boiled or off-gassed and will cause off-flavors in beer
• Dialysis patients: both chlorine and chloramine must be removed from water used in dialysis