NI Water is considering closing off the area around its water treatment works at Lough Bradan, outside Drumquin, if quad bike racers continue to cause damage to the area.
In the latest incident, NI Water say a fence was broken at Lough Lee, which is in the Lough Bradan catchment.
The damaged fence was repaired at the end of last week, a spokesperson said.
But Stewart Walsh, NI Water area manager, has appealed to the public to be vigilant and report anti-social behaviour, including the use of numerous quad bikes, in the Lough Bradan area.
He said, “The whole community needs to help us put a stop to this behaviour before this impacts on vital water services, which are essential for the local community.
“NI Water strictly prohibits the use of scramblers or quad bikes on our sites and would urge those involved to cease this activity immediately. What may seem like harmless fun is in actual fact an extremely dangerous activity and it risks damaging vital water supply resources.
“This activity, plus recent incidents of vandalism, has been reported to the PSNI and we are actively working with them for a permanent resolution.”
Mr Walsh warned that NI Water is now considering closing off the area to the entire public if the anti-social behaviour continues.
“We understand people want to make the most of these scenic areas, particularly over the summer months.
“But we would ask everyone to respect them,” he added.
Any inappropriate behaviour or vandalism can be reported to the police on 101 or Waterline 03457 440088.