In a winner-takes-all clash, it was the Merseysiders who cruised home to leave them requiring just one point to be crowned champions.
That could come when they face Prestfield on April 16 after Adam Shiffman (2) and Jordan Brookes edged them closer to the championship.
Haroldeans boss Mike Bloomberg said: "It was a very tough game, all credit to Reich, they battled for 90 minutes.
"The goal by Jordan on the stroke of half-time altered my teamtalk.
"It settled us down. And then two goals in the second-half by Adam sealed it.
"Paul Harris was outstanding in midfield, as was Zak Goldsmith at centre back, but there were strong performances throughout.
"Like they have done all season, everyone stepped up when they were needed."
Haroldeans will be confident of picking up the draw they need later this month and Bloomberg added: "We would love to get the point required to get the job done against Presfield.
"We want as many people as possible to come cheer the boys to the title.
"The players thoroughly deserve it for the attitude and application they've shown all season, as well as the outstanding football they team have played."
Reich White director of football Mike Gaswirth had no complaints and concedes his side's title bid is all over.
Gaswirth added: "It's more or less done.
"We had our strongest side out, besides some absent students, so there's no complaints. They were the better side.
"We haven't played 11-a-side for six weeks now and that made a big difference. It's not an excuse, but a reality."
Elsewhere, Maccabi Manchester Blue continue maintained their end-of-season from with a 3-0 win over Prestfield.
Ben Gould's brace and a Harry Margolis strike maintained their push for the top four.
Blues boss Jonny Rose said: “I’m really happy with the way we are playing. Everyone is pulling in the same direction.
“A top four finish is still in our sights.”
Maccabi Manchester Yellow staged a shock turnaround to book their place in the Shonn Trophy semi finals.
A 3-0 second-leg win saw them overturn the heavy deficit and progress 4-3 on aggregate over Reich Insurance Blue.
Goals from Moishe Hasid, Rafi Newman and Aaron Englander stunned managerless Reich Blue in the last-eight tie.
