Trihalomethanes in Tap Water and Colorectal Cancer Risk

The Hidden Risk in Your Glass

Every time you turn on the kitchen tap, you might be exposing yourself to trihalomethanes (THMs). These are chemical byproducts formed when chlorine reacts with organic matter in our water supply. A 2026 study published in Environment International analyzed 1,037 colorectal cancer cases and 2,100 controls to see how these chemicals interact with our genetics.

The researchers identified specific genetic variants that modulate colorectal cancer risk in relation to long-term exposure to chloroform and total trihalomethanes (TTHM). By integrating environmental data with genetic analysis, the study confirms that these common water contaminants are not just background noise—they are active factors in how our bodies process environmental toxicity.

What You Can Do Now

You cannot control the municipal water treatment process, but you can control what comes out of your faucet. Relying on standard tap water without filtration means you are likely ingesting these disinfection byproducts daily. The most effective way to mitigate this exposure is to install a high-quality water filtration system capable of reducing chlorine and its associated byproducts.

If you are concerned about what is flowing through your pipes, it is time to audit your home’s water filtration setup. We have curated a selection of non-toxic home alternatives designed to help you remove these contaminants at the point of use. Don't wait for the next report to decide that your water quality matters.

Source: Moratalla-Navarro F, Obón-Santacana M, Rius-Sansalvador B, Guinó E, Moragas N (2026). Environ Int.