The state’s maximum contaminant level for perchlorate is 2.0 ppb.
According to the town, the contaminant interferes with the normal function of the thyroid gland and has the potential to affect growth and development and could cause brain damage and other adverse effects, particularly in fetuses and infants.
Town officials said that there are six sources of drinking water in the town and only the Fresh Pond Well is impacted.
The sample was taken on April 6 and the laboratory notified the town of the results verbally on April 14, when another sample was collected.
That sample found that there was 2.94 ppb of perchlorate, with the average of both samples is 2.57 ppb.
The well is located off of Carriage Shop Road in East Falmouth and has been tested quarterly for perchlorate.
The most recent test on January 3, 2017, detected 1.6 ppb of perchlorate.
Town officials said that the inorganic chemical is widely used as an oxidizer in fireworks and other industrial products and appears in solutions used to disinfect drinking water or to bleach clothing.
The Falmouth Water Department will be investigating the situation and evaluating next steps in cooperation with the state’s Department of Environmental Protection.