Apr 23, 2018

Bay Area Water Trihalomethane Now at Safe Level Following Drought Increase

Recent drought conditions have led to an increase in contaminants

Bay Area waters return to safe level of THM contaminant

Despite a recent uptick in contaminant content, water sourced from the Bay Area does not currently pose any significant threat to human health. Recent drought conditions throughout California have led to an increase in Trihalomethane (THM) found in the area’s drinking water, but levels have since subsided to a safe volume.

East Bay Municipal Utility District released a report in June 2017 outlining the new influx of THM into the water supply. THM can increase the potential for cancer when consumed in large amounts, though it is commonly found in water systems.

The water that services the Bay Area is sourced from Sierra Nevada and no industrial pollutants are allowed in the water. Despite this, THM is able to form when microbes bind with chlorine.

“Animals are going to defecate, birds are going to drop bird droppings into the reservoirs,” said Charlotte Smith, campus public health lecturer. “Operators will add chlorine. The chlorines bind with small organic molecules. That product we call a disinfection byproduct. THM is the most common.”

According to Smith, THM levels in Bay Area water have already returned to normal following the abnormal spike, adding that THM only becomes carcinogenic at significantly high levels. The THM was able to thrive in the drought conditions as a result of an increased amount of organic matter found in the water.

Mercury is also a substance of interest for water officials in the area, as humans consume fish affected by mercury, but state officials are currently working to keep levels in check.