Jared from Idaho writes:

I heard that there might be stuff in tap water that causes cancer. Is that true?

Hi Jared

Yes, it’s true that there is a chance for there to be some suspected cancer causing chemicals in the water called trihalomethanes, or THM’s.  THM’s can be formed when naturally occurring organic chemicals in raw water supplies are combined with chlorine.

Fortunately, this is a well known chemical process and is heavily regulated. Health professionals have determined that a safe level of THM’s where the body’s natural processes can easily deal with and remove THM’s is 100 parts per billion.

The amount of THM’s or if THM’s are even formed are determined by many factors. The water source (river water has a higher chance than ground water because it contains more organics), pH, alkalinity, temperature, and many other factors. Water plants strive to remove as many organics as possible through processes like coagulation, flocculation, advanced oxidation, before chlorine is added as a disinfectant. The result is that most water supplies have THM levels well below 100 parts per billion, and some have zero THM’s.

Health professionals state that at or under 100 parts per billion there is no cause for alarm, and I tend to agree. There is more danger from external radiation and genetic disposition for cancer than with the low THM levels in water. However, if you want to take any and all chances away, activated carbon filters will reduce and remove THM, even in the minute quantities that are found in drinking water.

Activated carbon is used in inexpensive Jug Filters, Tap Filters, and under sink filters.

I hope that helps.

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