Chlorine Byproducts in Tap Water Affect Your Thyroid

The chlorine that disinfects your tap water creates byproducts that mess with your thyroid. Trihalomethanes and haloacetic acids are forming in your water and affecting thyroid function.

What the Study Found

A 2026 study measured urinary trihalomethanes and haloacetic acids (chlorine disinfection byproducts) and found their mixed exposure affects thyroid function. The study used integrated assessment frameworks to quantify the contribution of each chemical to thyroid disruption.

These byproducts form when chlorine reacts with organic matter in water. You're exposed by drinking, showering, and swimming.

What You Can Do

Use a water filter that removes chlorine and its byproducts (activated carbon works well). Ventilate the bathroom during hot showers to reduce inhalation exposure. Consider a whole-house water filter.

Browse our non-toxic kitchen alternatives for water filtration options.

Also see glass food containers for safer alternatives.

Source: Chlorine Byproducts and Thyroid Study (2026).