Chloramines in Drinking Water

🩨 Health Effects

At normal disinfectant levels, chloramines are not a significant health risk for most people. High levels (above the MCL) can cause eye and nose irritation and stomach discomfort. People on kidney dialysis must use special water treatment since chloramines can enter the bloodstream through dialysis.

📍 Sources in Water

Chloramines are added intentionally to disinfect water and to maintain a longer-lasting residual than free chlorine. Formed by reacting chlorine with ammonia. Many utilities use chloramine to reduce TTHM and HAA5 formation.

✅ What To Do

No action needed at permitted levels for the general public. If you are on kidney dialysis, notify your provider about your water treatment type. Whole-house carbon filters can reduce chloramine for sensitive individuals.

📜 Regulation History

The EPA set the maximum residual disinfectant level (MRDL) for chloramines at 4 mg/L under the Stage 1 Disinfectants and Disinfection Byproducts Rule in 1998. This is measured as a running annual average of chloramine residual in the distribution system. The WHO guideline for monochloramine is 3 mg/L, slightly stricter than the US standard.

🔬 How To Test Your Water

Total chloramine test kits using DPD reagent are available for $15-$25 and provide quick results. Certified lab tests cost $20-$30. Ask your utility whether they use chloramine or free chlorine. Standard pool/spa chlorine test kits often cannot distinguish between free chlorine and chloramine, so use a kit that measures both.

💧 Which Filters Remove Chloramines?

Catalytic carbon filters are the most effective at removing chloramine (standard carbon filters are much less effective). Whole-house catalytic carbon systems are ideal for chloramine removal throughout the home. Reverse osmosis with a catalytic carbon pre-filter is effective for drinking water. Look for NSF/ANSI 42 certification for chloramine reduction.

🔗 Related Contaminants