The Massachusetts Water Resources Authority says someone cut the locks to three hatches at one of its aqueducts in Framingham.
The incident occurred at the Hultman Aqueduct, which is one of the two lines that carry drinking water to the Greater Boston area.
The three padlocks were cut from separate access hatches located at approximately half-mile intervals along the aqueduct. Police say there is evidence of an attempt to cut a fourth lock.
State Police are investigating, though they say “there is no evidence of any crime other than vandalism.”
The MWRA says it doesn’t appear anyone tried to tamper with the water supply and there does not appear to be any contamination or changes in water quality.
Last month, State Police stepped up patrols at public water supplies after seven people were caught trespassing at the Quabbin Reservoir in Belchertown.