I’ll start by saying that out of the couple hundreds of samples we have taken in Kula and Lahaina neighborhoods thus far, we have only found clear signs of wildfire related contamination in a few fringe cases. This result matches what Maui DWS is finding as well, which supports their decision to begin lifting the do-not-use advisories in some areas.
Although we have not been finding many fire related VOCs in our tap water samples, we have been finding a group of chemicals known as disinfection by-products, specifically Trihalomethanes (THMs). Water utilities must provide safe drinking water to customers and this is achieved nearly everywhere in the country by using chlorination to kill waterborne pathogens that can make us sick. When chlorine or chloramines interact with organic matter, they react to form unwanted and generally unhealthy chemicals that remain at detectable levels in tap water. We explain this in greater detail in our FAQ about THMs. While the presence of THMs is expected in any public water system, these chemicals can have negative health effects at high enough concentrations.
For the most part, the levels of THMs we’re seeing in Kula and Lahaina are below the regulatory action level of 80 ppb for total THMs. However, in many of our samples the concentrations are actually pretty close to the limit, and we have seen some go above. While levels of total THMs below the 80 ppb standard are not considered to be a health or safety issue by HI DOH and Maui DWS, guidance from other states and references suggest that these lower levels could be of concern.
The good news is that we aren’t finding levels of any VOCs that would overwhelm the capacity of standard activated carbon water filters. There are many filters out there and while we aren’t in the business of recommending brands, we are testing the effectiveness of people’s filters when we can. We will continue to test tap water, filtered and unfiltered, and are happy to take multiple samples for those who may be interested. If you would like a another sample please sign up on our requests form again and indicate you are seeking a repeat sample.