Irish Water has said 90% of customers who paid a bill during the first billing cycle have already paid their second bill.
It said 150,000 additional households began paying for the first time during the second billing cycle.
Speaking to RTÉ’s Morning Ireland Mr Murphy said the overall picture was not clear and he called on Irish Water to publish a listing of those who have paid all their bills so a clear analysis can be made.
He said he believed people have been bullied into paying for water charges and politicians will hear about it on the door steps when they campaign for the general election.
"We want them to put up on their website they sent out this many bills for the second bill and this is how many people have paid it and it's in everyone's interests who sees those figures,” said Mr Murphy.
“The reality is that this is a company who can't even give away a €100. They had to extend the deadline after saying they wouldn't again. It just shows the level of opposition that exists to Irish Water. It will be reflected in the election campaign."
Mr Murphy's comments come ahead of tonight's midnight deadline for householders to register for the €100 Water Conservation Grant.
The Department of Social Protection said that by 11.35am this morning 859,034 applications for the grant had been received.