There were disturbances outside Waterford city earlier as more than 100 residents protested at attempts to install water meters.
Gardaí said a number of residents were at the entrances into four housing estates in Ferrybank.
Residents from Abbey Park, Fíodh Mór, Ard Glas and Leaca Ard stood at the entrances and said they will remain there overnight.
The protesters said they do not want Irish Water to install the meters.
They said they are angry about what they see as double taxation but also about water quality in the area, saying there are excessive levels of lime in the water.
The theft of equipment for installing water meters from a housing estate in Ferrybank last night is being investigated by gardaí.
It is believed 250 plastic barriers, cones and signs were taken from Fíodh Mór sometime between 7pm and 11.30pm.
Gardaí are maintaining a presence and are continuing to monitor the situation at Ferrybank, which began on Monday.
Irish Water said it was aware of the situation in Ferrybank.
It said: "Irish Water will be assisting gardaí in their investigations into the matter."