Workers installing water meters have been followed home, labelled as paedophiles and assaulted in the course of their working day.
Irish Water boss John Tierney said that metering protests had taken a sinister turn in recent months which had resulted in workers being violently assaulted and labelled as child molesters.
A loaded gun had been produced, human waste left in boundary boxes used to fit meters, and images of workers posted online. About 50 assaults have been reported to Irish Water, including hot water being thrown at workers, two incidents where staff have been threatened with a firearm, and metering crews punched, kicked, bitten and spat at.
"In the last six months we have experienced a difficult element to the protests," Mr Tierney said.
"Incidents where people have been spat at; where excrement has been put in the boundary boxes, where staff have been headbutted, where a loaded gun has been produced. Vehicles have been driven at workplaces. A staff member was attacked outside his home and bitten as part of the assault.
"We have had staff members followed home and told: 'We know where you live'. Tyres being slashed where a staff member was in a shop. A relatively young staff member had a photograph put up online and the word 'paedophile' put with it - that's pretty disturbing."
Mr Tierney said that while he hadn't personally received any threats, there had been "some concerns" raised about his property.
"A number of cases have been reported to gardai but in some cases people are too afraid to report," he said. "This isn't about me at all. I would be far more concerned about what is happening to people who are genuinely coming to work."
About 1,300 people are employed on the water metering programme. Half of all workers come from small and medium-sized companies "which have had a difficult time in the last six or seven years", Mr Tierney said. Another 20pc are drawn from the live register, while 10pc are graduates or school leavers.
"In the initial stages of the metering there were peaceful protests, and there are still people peacefully protesting. We have said on numerous occasions we respect the right of people to peacefully protest. The law does say Irish Water can install meters."
Irish Water also claimed emergency services had been prevented from assisting an injured worker. Gardai were investigating some incidents.