Tap, Bottled, and Filtered Water: SF Bay Chemical Study

A team of water technicians from SimpleLab, a water testing company, conducted a detailed analysis of chemical levels in hundreds of water samples from various sources, including bottled water, household tap water, and filtered tap water in the San Francisco Bay area. Their findings were published in the journal PLOS Water, shedding light on the quality of drinking water and how it varies depending on the source.

For decades, people in the United States believed that tap water in the average home was completely safe to drink. However, recent incidents like the Flint, Michigan crisis, where lead contamination severely impacted children, have raised concerns about water safety. As a result, many consumers have started questioning the quality of their drinking water, leading them to rely on water filters or opt for commercially sold bottled water.

The research team from SimpleLab set out to examine how these three main sources of drinking water compare in terms of chemical contamination. They collected 100 samples of bottled water, 603 samples of unfiltered tap water, and 111 samples of filtered tap water using a Brita filter. Their analysis showed that most of the water samples met the federal drinking water health standards, which is reassuring for consumers.

However, the study revealed a significant difference in chemical levels between the different water sources. Both filtered water and bottled water had nearly identical levels of chemicals, while tap water had much higher concentrations. The primary chemicals of concern were trihalomethanes, which are by-products of the chlorination process used to disinfect water. These chemicals were found in varying amounts in all three sources of water.

Trihalomethanes are associated with several long-term health risks, including liver damage, developmental delays, and an increased risk of certain cancers. While these findings may be concerning, the researchers emphasized that consuming small amounts of trihalomethanes or other detected chemicals is unlikely to pose immediate health risks. They clarified that their study is not meant to cause alarm but rather to highlight the benefits of using filters for better water quality.

In their conclusion, the researchers recommended that most consumers would benefit from using a water filter for their tap water, as it can effectively reduce chemical contamination and also improve the taste of the water. This practical step can provide an added layer of protection for consumers and peace of mind regarding the quality of the water they consume daily.