On Friday, when workers arrived at the water treatment facility in Manapalan, they "heard cries for help" and discovered a man lodged inside a 20-inch pipe outside of a storage tank.
The facility, which is operated by United Water, supplies drinking water to about 40,000 customers.
The man has been identified as 26-year-old Asaf Mohammed.
Director of operations, Jim Mastrokalos, told NJ.com:
He must have traversed through a basin and climbed up into a pipe for reasons unknown at this time."
The plant is surrounded by barbed wire fencing and workers are still trying to determine how the man was able to gain access to the facility without detection.
Mohammed has been charged with fourth-degree criminal trespassing.
In May 2013, seven Muslims from Pakistan, Saudi Arabia and Singapore were arrested in the middle of the night at the Quabbin Reservoir which supplies drinking water to the city of Boston as well as dozens of other Massachusetts communities.
The group of two women and five men told the state trooper who discovered them, that they were all chemical engineers and simply wanted to check out the facility.
Three locks had been cut to gain access to the reservoir.
Despite the fact that this incident occurred only a month after the Boston Marathon bombing, and the serious threat that could have been posed to a drinking water facility, no charges were ever filed against the group of trespassers.
The Massachusetts State Police appealed the decision, but to no avail.
The names of the 'chemical engineers' were never released to the public, and their whereabouts are currently unknown.