Jobs will be called off in £250,000-plus work packages, which have been divided into regional lots covering north Wales, the south east and south west.
Alun Griffiths, Dawnus Construction, May Gurney and Murphy picked up all three regions through the negotiated framework procedure.
Welsh Water major civils
North
Alun Griffiths
Dawnus Construction
Graham Construction
May Gurney
Mulcair
Murphy
William Hughes
South east
Alun Griffiths (Contractors)
Dawnus Construction
Dean & Dyball
Lewis Civil Engineering
May Gurney
Murphy
Graham Construction
South west
Alun Griffiths
Dawnus Construction
Dean & Dyball
Lewis Civil Engineering
Murphy
May Gurney
Young Bros
Works will cover general maintenance and civil engineering, including sewer modernisation and gravity pipeline work over a four year term.