A goal from Courtney Duffus and Paul Keegan’s late penalty consigned Limerick to their third successive defeat and their second loss at home this term.
Kenny Browne returned to the Waterford line-up in place of Garry Comerford from the recent win over Shamrock Rovers and John Martin replaced the injured Dean O’Halloran.
Martin fired a cross into the area inside the opening five minutes but Duffus just failed to get his toe to the ball while nobody anticipated a low Tony Whitehead centre at the other end.
Limerick keeper Brendan Clarke had to be alert to keep out a Duffus effort and the home side failed to take advantage of a massive throw in from Will Fitzgerald.
Martin was again involved 16 minutes in, beating the offside trap to feed Duffus but his drive was deflected into the hands of Clarke.
Limerick should have gone one up after Fitzgerald was left on a one-on-one with Lawrence Vigouroux, but the Waterford keeper held his ground and saved.
The Shannonsiders were enjoying the lion’s share of possession at this point with Duggan testing Vigouroux.
But the visitors edged ahead midway through the half after Duffus raced onto a Gavan Holohan pass to net his fourth goal of the season with a low drive past Clarke.
Duggan had a glorious chance to level 10 minutes from the break but Vigouroux saved a point-blank effort from the Limerick captain from a Connor Ellis pass and stopped another drive from the Lims skipper moments later.
Waterford, however, should have been two up at the break with Gavan Holohan chipping wide after sleepy defending from a Bastien Hery through ball.
Duggan was just inches away from getting his head to a Fitzgerald cross immediately after the break, Fitzgerald once again lifting his side with positive play.
But Waterford should have doubled their advantage after Limerick’s defence was caught napping again and John Kavanagh saw his
effort cleared off the line by Kelly.
However, it was all Waterford in a 10-minute spell either side of the hour mark, the visitors retaining possession and threatening, courtesy of Stanley Aborah, Hery, and Duffus who was denied by Clarke.
Another long throw from Fitzgerald lifted the pressure 20 minutes from time, the Limerick striker almost hitting the penalty spot with a massive delivery. Vigouroux saved from Kelly and a penalty appeal was waved aside after a foul on Ellis.
Hery, a former Limerick favourite, was greeted with ironic jeers after his drive flew high and handsome and Limerick sub Jew McGowan had a penalty appeal dismissed.
Holohan couldn’t get his head over a Hery cross from the right to seal the win and Hery sent another flying across the area inside the last ten minutes.
Waterford put the matter beyond dispute seven minutes from time, Paul Keegan blasting his penalty into the end containing the away fans after Ismahail Akinade was fouled by Whitehead.
Limerick huffed and puffed late on to try and reduce the deficit but the visitors had a David Webster header hacked off the line from a Hery corner in the 90th minute.
Clarke, B Dennehy, Dennehy inj (Brouder 46), Whitehead, Kelly, Maguire (O’Sullivan 60), Cantwell, Duggan, Fitzgerald, Coleman, Ellis (McGowan 84)
Vigouroux, Browne, Kavanagh, Aborah, Webster, Barnett, Hery, Holohan (Daly 86). Keegan, Duffus (Puri 86) Martin (Akinade 64)
T Connolly (Dublin)