Four first half tries from Paul Smithson (2), Hywel Davies and Matthew Murphy along with 11 points from the boot of Gareth Powell won the game for the Waterwheelers. Blackwood showed fighting spirit to keep in touch but they couldn't capture the crucial win which would have put them level on points with Beddau.
RGC 1404 cemented second place thanks to a 57-6 drubbing of Bridgend Athletic at Parc Eirias.
Harri Evans and Tom Blackwell both scored a brace as the North Walians ran in nine unanswered tries.
Cardiff Met moved up to fifth in the Swalec Championship with a stylish 50-0 victory over an ill disciplined Newbridge side.
The men from Gwent had two players sent off, but the students looked far superior and ran in seven tries in the blow-out victory- Joe Smith, Jake Henry and Guy Wood with the pick of the scores for Chris Davey's men.
Tata Steel ground out a 19-18 away win to Narbeth in a tense affair. The result means that Tata are now only two points behind their fourth placed opponents, although they have played three games more.
Pontypool fought hard to pick up a 16-3 win at Bargoed, while Bonymaen bagged a losing bonus point in their 3-9 loss to Llanharan.